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Quadratic Formula Worksheet




Given below are the Quadratic Formula Worksheet with Answers Class 10 Maths
Quadratic Formula
For the Quadratic equation
$ax^2 +bx +c =0$
Where a, b and c are real numbers and a ≠0
Roots of the quadratic equation is given by Quadratic Formula
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$


Question 1. State which all quadratic equations have real roots, no real roots
a. $x^2 + 8x+7=0$
b. $3x^2 +5x+1=0$
c. $9x^2 +x -3=0$
d. $11x^2 +5x+1=0$
e. $10x^2 +3x+7=0$
f. $2x^2 -6x+3=0$
g. $2x^2 -x-2=0$
Solution
Nature of roots of Quadratic equation
S.no
Condition
Nature of roots
1
$b^2 -4ac > 0$
Two distinct real roots
 
2
$b^2-4ac =0$
One real root
3
$b^2-4ac < 0$
No real roots
 
Real roots: :(a), (b), (c),(d) ,(e),(f),(g)
No real roots : (d) ,(e)

Question 2. Find the roots of the quadratic equation using Quadratic Formula
a. $x^2-3x-10=0$
b. $x^2 -11x+30=0$
Solution
a.
$x^2-3x-10=0$
Comparing this to $ax^2 + bx +c=0$
We have a =1, b=-3 and c =-10
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
or $x=\frac {3 \pm \sqrt {9 +40}}{2}$
$x=\frac {3 \pm 7}{2}$
or
$x=\frac {3 + 7}{2}$ or $x=\frac {3 - 7}{2}$
So roots are x=5 and -2
b. $x^2 -11x+30=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=-11 and c =30
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
$x=\frac {11 \pm \sqrt {121 -120}}{2}$
$x=\frac {11 \pm 1}{2}$
or
$x=\frac {11 + 1}{2}$ or $x=\frac {11 - 1}{2}$
So
Roots are 5 and 6

Question 3. Find the roots of the quadratic equation using Quadratic formula
a. $x^2 +4x-5=0$
b. $2x^2-7x+3=0$

Solution
a.
$x^2 +4x-5=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=4 and c =-5
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$  
So
x=1 or -5
b.
$2x^2-7x+3=0$
Comparing this to $ax^2 + bx +c=0$
a=2, b=-7 and c =3
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
So
x=1/2 or 3
 

Question 4
Find the roots using Quadratic Formula
a. $x^2+ (7 - x)^2= 25$
b. $y^2+ (y+2)^2 =580$
c. $11x^2 -31x -6 =0$
d. $9 -y - 10y^2 =0$
e. $14x +4x^2 =2x -5$
f. $3y^2 + 4y=2(y+4)$
g. $2x^2 -5x +3 =0$
h. $\frac {x+1}{x-1} + \frac {x-2}{x+2} =3$ ,$x \neq 1$, $x \neq -2$
i. $x^2 + 5x =-1$
j. $ \sqrt {2x + 9} + x=13$
k. $\frac {1}{a} + \frac {1}{b} + \frac {1}{x} = \frac {1}{a+b+x}$
l. $ \sqrt {2} x^2 + 7x + 5 \sqrt {2}=0$
m. $ \frac {3}{x+1} + \frac {4}{x-1} = \frac {29}{4x-1};x \neq 1,-1,1/4$
Solution
a.
$x^2+ (7 - x)^2= 25$
$x^2 + 49 +x^2 -14x =25$
$2x^2 -14x + 24=0$
$x^2 -7x + 12=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=-7 and c =12
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
So
x=3 or 4

b.
$y^2+ (y+2)^2 =580$
$y^2 + y^2 + 4 + 4y =580$
$2y^2 + 4y -576=0$
$y^2 + 2y-288=0$
Comparing this to $ay^2 + by +c=0$
a=1, b=2 and c =-288
$y= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
So
y=16 or -18

c.
$11x^2 -31x -6 =0$
Comparing this to $ax^2 + bx +c=0$
a=11, b=-31 and c =-6
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
So
x=3 or -2/11

d.
$9 -y - 10y^2 =0$
$10y^2 + y -9=0$ Comparing this to $ay^2 + by +c=0$
a=10, b=1 and c =-9
$y= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
So
y=-1 or 9/10

e.
$14x +4x^2 =2x -5$
$4x^2 + 12x +5=0$
Comparing this to $ax^2 + bx +c=0$
a=4, b=12 and c =5
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
so x=-1/2 or -5/2

f.
$3y^2 + 4y=2(y+4)$
$3y^2 + 4y = 2y + 8$
$3y^2 + 2y -8=0$
Comparing this to $ay^2 + by +c=0$
a=3, b=2 and c =-8
$y= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
so y=-2 or 4/3

g.
$2x^2 -5x +3 =0$
Comparing this to $ax^2 + bx +c=0$
a=2, b=-5 and c =3
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
so y=3/2 or 1

h.
$\frac {x+1}{x-1} + \frac {x-2}{x+2} =3$
$ \frac { (x+1)(x+2) + (x-2)(x-1)}{(x-1)(x+2)}=3$
$ x^2 + 3x +2 + x^2 -3x + 2= 3(x^2 +x -2)$
$2x^2 +4 = 3x^2 +3x -6$
$x^2 +3x -10=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=3 and c =-10
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
so x=-5 or 2


i.
$x^2 + 5x =-1$
$x^2 + 5x +1=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=5 and c =1
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
so,$x = \frac {-5 + \sqrt {21}}{2}$ or $x= \frac {-5 - \sqrt {21}}{2}$

j.
$ \sqrt {2x + 9} + x=13$
$ \sqrt {2x + 9} = 13-x$
Squaring both the sides $2x+9 = (13-x)^2$
$2x+ 9 = 169 + x^2 -26x$ $x^2 -28x +160=0$ Comparing this to $ax^2 + bx +c=0$
a=1, b=-28 and c =160
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
x=20,8
k.
$\frac {1}{a} + \frac {1}{b} + \frac {1}{x} = \frac {1}{a+b+x}$
$\frac {bx + ax + ab}{abx} =\frac {1}{a+b+x}$
$ (bx + ax + ab)(a+b+x) = abx$
$abx + b^2x + bx^2 + a^2 x+ abx+ ax^2 + a^b + ab^2 + abx = abx$
$x^2(a + b) + x(a^2 + b^2 + 2ab) + ab(a+b) =0$
$x^2(a+b)+ x(a+b)^2 + ab(a+b) =0$
Dividing by (a+b)
$x^2 + x(a+b) + ab= 0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=(a+b) and c =ab
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
x=-a,-b

l.
$ \sqrt {2} x^2 + 7x + 5 \sqrt {2}=0$
Comparing this to $ax^2 + bx +c=0$
$a=\sqrt {2}$, b=7 and $c =5 \sqrt {2}$
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
$x = \frac {-7 \pm \sqrt {7^2 -4 \times \sqrt {2} \times 5 \sqrt {2}}}{2\sqrt {2}}$
$x=\frac {-7 \pm \sqrt {49-40}}{2\sqrt {2}}$
or
$x= -\sqrt {2}$ or $x= -\frac {5\sqrt{2}}{2}$

m. $ \frac {3}{x+1} + \frac {4}{x-1} = \frac {29}{4x-1};x \neq 1,-1,1/4$
$ \frac {3(x-1) + 4(x+1)}{(x+1)(x-1)} = \frac {29}{4x-1}$
$\frac {7x +1}{x^2 -1} = \frac {29}{4x-1}$
$ (7x+1)(4x-1) = 29(x^2-1)$
$28x^2 -7x+4x -1 = 29x^2 -29$
$x^2 + 3x-28=0$
Comparing this to $ax^2 + bx +c=0$
a=1, b=3 and c =-28
$x= \frac {-b \pm \sqrt {b^2 -4ac}}{2a}$
x=-7 or 4
Question 5
Solve the below quadratic equation using quadratic formula a. $x^{2} + 4 x = -1$
b. $3 x^{2} + 3 x - 1 = 0$
c. $3 x^{2} + 2 x = 2$
d. $2 x^{2} = 1 -3x$
e. $5 x^{2} = 2 (1-x)$
f. $4 x^{2} + 2 x = 0$
g. $4x( x+ 1) =1$
h. $\frac {1}{x+1} + \frac {2}{x+2} = \frac {4}{x+4},x \neq -1,-2,-4$
i $x^{2} + 2 x - 2 = 0$
j. $4 x^{2} + 4 x - 2 = 0$
k. $3 x^{2} + 4 x + 1 = 0$
l. $4 x^{2} + 4 x - 2=0$
m. $x^{2} + 3 x + 2 = 0$
n. $5 x^{2} + x = 0$
o. $ \frac {16}{x} -1 = \frac {15}{x+1},x \neq 0,-1$
Solution
a. $x = -2 - \sqrt{3}, x = -2 + \sqrt{3}$
b. $x = - \frac{1}{2} + \frac{\sqrt{21}}{6}, x = - \frac{\sqrt{21}}{6} - \frac{1}{2}$
c. $x = - \frac{1}{3} + \frac{\sqrt{7}}{3}, x = - \frac{\sqrt{7}}{3} - \frac{1}{3}$
d. $x = - \frac{3}{4} + \frac{\sqrt{17}}{4}, x = - \frac{\sqrt{17}}{4} - \frac{3}{4}$
e. $x = - \frac{1}{5} + \frac{\sqrt{11}}{5}, x = - \frac{\sqrt{11}}{5} - \frac{1}{5}$
f. $x = - \frac{1}{2}, x = 0$
g. $x = - \frac{1}{2} + \frac{\sqrt{2}}{2}, x = - \frac{\sqrt{2}}{2} - \frac{1}{2}$
h. $x = 2 +2 \sqrt{3}, x = 2 - 2 \sqrt{3}$
i. $x = -1 + \sqrt{3}, x = - \sqrt{3} - 1$
j. $x = - \frac{1}{2} + \frac{\sqrt{3}}{2}, x = - \frac{\sqrt{3}}{2} - \frac{1}{2}$
k. $x = -1, x = - \frac{1}{3}$
l. $x = - \frac{1}{2} + \frac{\sqrt{3}}{2}, x = - \frac{\sqrt{3}}{2} - \frac{1}{2}$
m. $x = -2, x = -1$
n. $x = - \frac{1}{5}, x = 0$
o.$x = - 4, x = 4$


Summary

This Quadratic Formula Worksheet Class 10 Maths is prepared keeping in mind the latest syllabus of CBSE . This has been designed in a way to improve the academic performance of the students. If you find mistakes , please do provide the feedback on the mail.You can also download through below link
Download Quadratic Formula worksheet as pdf


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