polynomials

Find the value of x + y + z, if x2 + y2 + z2 = 18 and xy + yz + zx = 9.

• 9

• 3

• 6

• 8

If x = –2 and x2 + y2 + 3xy = –5, then find y.

• -2

• 3

• -4

• 9

Factorise: x2 + (a + b + c)x + ab + bc

• (x + a)(x + b + c)

• (x + a)(x + a + c)

• (x + b)(x + a + c)

• (x + b)(x + b + c)

(x + y) 3 – (x – y) 3 – 6y(x2 – y2) =

• y3

• 2y3

• 4y3

• 8y3

Which of the following is a cubic polynomial?

• 2 3+ 4 x +x2

• - x – x2 – 7x3

• 9

• 2 – 3x2 – 9x

The common quantity that must be added to each term of a2 : b2 to make it equal to a : b is

• ab

• a + b

• a – b

• a b

The value of the polynomial 5x – 4x2 + 3, when x = – 1 is

• - 6

• 6

• 2

• - 2

If f(x) = x3 – 3x2 + 4x + 50, then f(–3) =

• -16

• -12

• -20

• -10

Factors of (42 – x – x2) are

• (x – 7), (x – 6)

• (x + 7), (x – 6)

• (x + 7), (6 – x)

• (x – 7), (x + 6)

• 4 + x

• 2 + x

• 1 – x

• x + 1