Question

7.
Find the value of each of the following
expressions when x = -1, y = -2 and z = 2.
(a) -2x (3x - 4y) + 2y (6y - 9z) + 2z (4z - x)
(b) 7 (x - y - z²) - 2 (z - x²)​

Answer 1

HERE IS UR ANSWER DEAR,

refer to the attachment

Answer 2

Answer:

(a) 166

(b) -23

Step-by-step explanation:

(a) -2(-1)[3(-1)-4(-2)] + 2(-2)[6(-2) - 9(2)] + 2(2)[4(2)-(-1)]

= 2[-3+8] + (-4)[-12-18] + 4[8+1]

= 2×5 + (-4)×(-30) + 4×9

= 10 + 120 + 36 = 166

(b) 7[-1-(-2)-2^2] - 2[2-(-1)^2]

= 7[-1+2-4] - 2[2-1]

= 7×-3 - 2×1 = -21-2 = -23