The Total solution for NCERT class 6-12
The number of polynomials having zeroes -2 and 5 is(a) 1(b) 2(c) 3(d) more than 3
Answer - 31 : - (d)
Hence, the required number of polynomials are infinite i.e.,more than 3.
If one of the zeroes of the quadratic polynomial (k – 1)x2 + kx + 1 is -3, then the value of k is
Answer - 32 : - (a)
The zeroes of the quadratic polynomial x2 + 99x + 127 are(a) both positive(b) both negative(c) both equal(d) one positive and one negative
Answer - 33 : - (b)
If the zeroes of the quadratic polynomial x2 + (a + 1) x + b are 2 and -3, then(a) a = -7, b = -1(b) a = 5, b = -1(c) a = 2, b = -6(d) a = 0, b = -6
Answer - 34 : - (d)
Given that one of the zeroes of the cubic polynomial ax3 + bx2 + cx + d is zero, the product of the othertwo zeroes is
Answer - 35 : - (b)
The zeroes of the quadratic polynomial x2 + ax + a, a ≠ 0,(a) cannot both be positive(b) cannot both be negative(c) area always unequal(d) are always equal
Answer - 36 : -
(a) Let p(x) = x2 + ax + a, a ≠ 0On comparing p(x) with ax2 + bx + c, we geta = 1, b = a and c = a
So,both zeroes are negative.Hence, in any case zeroes of the given quadratic polynomial cannot both thepositive.
If one of the zeroes of the cubic polynomial x3 + ax2 + bx + c is -1, then the product of othertwo zeroes is(a) b – a + 1(b) b – a – 1(c) a – b + 1(d) a – b – 1
Answer - 37 : - (a)
Given that two of the zeroes of the cubic polynomial ax3 + bx2 + cx + d are 0, the third zero is
Answer - 38 : -
(a) Two of the zeroes of the cubic polynomialax3 + bx2 + cx + d = 0, 0Let the third zero be dThen, use the relation between zeroes andcoefficient of polynomial, we have
If one zero of the quadratic polynomial x2 + 3x + k is 2, then the value of k is(a) 10(b) -10(c) 5(d) -5
Answer - 39 : -
(b) Let the given quadratic polynomial be P(x) = x2 + 3x + kIt is given that one of its zeros is 2P(2) = 0=> (2)2 + 3(2) + k = 0=> 4 + 6 + k = 0=> k + 10 = 0 => k = -10
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 - 40 : -
(c) The zeroes of the given quadratic polynomialax2 + bx + c, c ≠ 0 are equal. If coefficient of x2 and constant term have the same signi.e., c and a have the same sign. While b i.e.,coefficient of x can be positive/negative but not zero.