Class 10 Maths Important Questions for Polynomials
Given below are the polynomials class 10 important questions with answers
(a) Concepts questions
(b) Calculation problems
(c) Multiple choice questions(MCQ)
(d) Short answer questions
(e) True and False
(f) Match the column
a. it cuts the x-axis at two points ,so 2 zeroes
b. it cuts the x-axis at four points ,so 4 zeroes
c. Since it does not cut the axis, so 0 zeroes
d. it cuts the x-axis at 1 points ,so 1 zero’s
e. it cuts the x-axis at 1 points ,so 1 zero’s
f. Since it does not cut the axis, so 0 zeroes
g. Since it does not cut the axis, so 0 zeroes
h. it cuts the x-axis at two points ,so 2 zeroes
a. Quadratic as parabola
b. Three zeroes,So cubic polynomial
c. Constant value polynomial
d. Linear polynomial
e. One zeroes but not straight line. So no appropriate match found
f. Quadratic as parabola
g. Quadratic as parabola
e. Cubic as has three zeroes ,two of them same
Multiple choice Questions
Question 1
Find the remainder when x4+x3-2x2+x+1 is divided by x-1
a.1
b.5
c.2
d. 3 Solution
Answer is ( c)
Let P(x) =x4+x3-2x2+x+1
Remainder when divide by x-1
P(1) = 1+ 1-2+1+1=2
Question 2
Which of these identities is not true? Solution
Answer is (d)
Question 3
If a and b are the zeroes of the polynomial x2-11x +30, Find the value of a3 + b3
a.134
b.412
c.256
d.341 Solution
a3 + b3= (a+b) (a2+b2-ab)=(a+b) {(a+b)2 -3ab}
Now a+b=-(-11)/1=11
ab=30
So a3+b3=11( 121 -90)=341
Question 4
S(x) = px2+(p-2)x +2. If 2 is the zero of this polynomial,what is the value of p
a.-1
b.1/2
c. -1/2
d. +1 Solution
S(2)=4p+0+2=0 => p=-1/2
Question 5
if the zeroes of the quadratic equation are 11 and 2 ,what is expression for quadratic
a. x2-13x+22
b. x2-11x+22
c. x2-13x-22
d. x2+13x-22 Solution
P(x) =(x-11)(x-2)
Question 6
p(x) = x4 -6x3 +16x2 -25x +10
q(x) = x2-2x+k
It is given
p(x) = r(x) q(x) + (x+a)
Find the value of k and a
a.2,-2
b. 5 ,-5
c. 7,3
d. 3,-1 Solution
Dividing p(x) by q(x) ,we get the remainder
(2k-9)x -(8-k)k +10
Comparing this with (x+a)
We get
K=5 and a=-5
Question 7 A cubic polynomial is given below
S(x) =x3 -3x2+x+1
The zeroes of the polynomial are given as (p-q) ,p and (p+q). What is the value p and q
a. p=1,q=√2 or -√2
b. p=1,q=2 or -2
c. p=1,q=1 or -1
d. None of these Solution
(a)
Question 8
If the zeroes of the quadratic polynomial ax2 + bx + c, c ≠ 0 are equal, then
a. c and a have opposite signs
b. c and b have opposite signs
c. c and a have the same sign
d. c and b have the same sign Answer
Given that, the zeroes of the quadratic polynomial ax2 + bx + c , c ≠ 0 are equal
Value of discriminant (D) has to be zero
b2– 4ac = 0
b2 = 4ac
Since L.H.S. (b2) can never be negative
R.H.S. also can never be negative.
a and c must have same sign
Question 9
What are the zeroes of the Polynomial $p(x)=6x^2 - 7x -3$
a. (3/2) , (-1/3)
b. (3/2) , (1/3)
c. (-3/2) , (1/3)
d. (-3/2) , (-1/3) Answer
$p(x)=6x^2 - 7x -3$
$p(x) = 6x^2 -9x + 2x -3 = 3x(2x -3) + 1(2x-3)=(3x+1)(2x-3)
So roots are (3/2) , (-1/3)
Hence option(a) is correct
Question 10
What are the zeroes of the Polynomial $p(x)=x^2 + 7x +10$
a. (2) , (-5)
b. (-2) , (5)
c. (2) , (5)
d. (-2) , (-5) Answer
$p(x)=x^2 + 7x +10$
$p(x) = x^2 + 5x +2x +10 = x(x +5) + 2(x+5)=(x+2)(x+5)
So roots are (-2) , (-5)
Hence option(d) is correct
True or False statement
P(x) =x-1 and g(x) =x2-2x +1 . p(x) is a factor of g(x)
The factor of 3x2 -x-4 are (x+1)(3x-4)
Every linear polynomial has only one zero
Every real number is the zero’s of zero polynomial
A binomial may have degree 6
1,2 are the zeroes of x2-3x+2
The degree of zero polynomial is not defined
Graph of polynomial (x2-1) meets the x-axis at one point
a.(x+6)(x+3)
b.(3x-1)(x-1)(x+1)
c.(x-1)(x-10)(x-12)
d. (2x+1)(4x2-2x+1)
Division of polynomial
s(x) =r(x) s(x) + w(x)
Find the value of r(x) and w(x) in each case
a. p(x) =x4+x3+2x2+3x+4
s(x) =x+2
b. p(x) =x4+4
s(x)=x2+x+1 Solution
a. r(x)=x3-x2 +4x-5 w(x)=14
b. r(x)=x2-x w(x) =x+4
More Practice Questions
Question 1.
If the polynomial f(x) = x4 -6x3 + 16x2 - 25x + 10 is divided by another polynomial x2 -2x + k, the remainder comes out to be x + a, find k and a. Answer
Dividend = Divisor X Quotient + Remainder
Dividend - Remainder = Divisor X Quotient
Dividend - Remainder is always divisible by the divisor.
Now, it is given that f(x) when divided by x2 -2x + k leaves (x + a) as remainder.
So f(x) -(x+a) is divided by x2 -2x + k
Now doing the division
Now remainder should be zero
(-10 + 2k)x + (10 - a - 8k + k2) = 0
-10 + 2k = 0 or k=5
Now (10 -a - 8k + k2) = 0
or 10 - a - 8 (5) + 52 = 0
or - a - 5 = 0
a =-5
Question 2. Find all the zeroes of the polynomial x4 - 3x3 + 6x - 4, if two of its zeroes are √2 and -√2 Answer
√2 , -√2, 2,1
Question 3. If p and q are he zeroes of the quadratic polynomial f(x) = x2 - 2x + 3, find a polynomial whose roots are:
p + 2, q + 2
(p-1)/(p+1) , (q-1)/(q+1)
Question 4. For what value of k, -7 is the zero of the polynomial 2x2 + 11x + (6k - 3)? Also find the other zero of the polynomial Answer
k= -3
The other root is 3/2
Question 5. What must be added to f(x) = 4x4 + 2x3 - 2x2 + x - 1 so that the resulting polynomial is divisible by g(x) = x2 + 2x -3? Answer
61x - 65
Question 6. Find k so that x2 + 2x + k is a factor of 2x4 + x3 - 14 x2 + 5x + 6. Also find all the zeroes of the two polynomials. Question 8. Find the zeroes of 2x3 - 11x2 + 17x - 6. Question 9. If (x - 2) and [x - ½ ] are the factors of the polynomials qx2 + 5x + r prove that q = r Answer
4q+10+r=0 -(1)
q/4 +5/2 +r=0 or q+10+4r=0 -(2)
Subtracting 1 from 2
3q-3r=0
q=r
Question 10. Find k so that the polynomial x2 + 2x + k is a factor of polynomial 2x4 + x3 - 14x2 + 5x + 6. Also, find all the zeroes of the two polynomials. Answer
For x2 + 2x + k is a factor of polynomial 2x4 + x3 - 14x2 + 5x + 6, it should be able to divide the polynomial without any remainder
Comparing the coefficient of x we get.
21+7k=0 or k=-3
So x2 + 2x + k becomes x2 + 2x -3 = (x-1)(x+3)
Now
2x4 + x3 - 14x2 + 5x + 6= (x2 + 2x -3)(2x2-3x-8+2k)
=(x2 + 2x -3)(2x2-3x-2)
=(x-1)(x+3)(x-2)(2x+1)
or x= 1,-3,2,=-1/2
Question 11. On dividing p(x) = x3 - 3x2 + x + 2 by a polynomial q(x), the quotient and remainder were x - 2 and -2x + 4, respectively. Find g(x). Answer
x2 - x +1
Question 12. a, b, c are zeroes of cubic polynomial x3 - 2x2 + qx - r. If a + b = 0 then show that 2q = r. Question 13. Find the remainder when x51 +51 is divided by (x+1). Question 14.
a,b and c are zeroes of polynomial x3 + px2 + qx + 2 such that a b + 1 = 0. Find the value of 2p + q + 5. Answer
By cubic polynomial equation, we have
a+b+c=-p
ab+bc+ac=q
abc=-2
Now given ab+1=0 or ab=-1
So abc=-2
(-1)c=-2 or c=2
