Question

Simplify the following expressions and find its value.
(a) 3(x^3 + xy) + 2 + xy, when x = 2 and y = -1
(b) 2(xy - 1) + 4 - (x^2 + xy), when x = -2 and y = -1
(c) 3(x^2 - xy) + 4 + xy, when x = -3 and y = -1​

Answer 1

Explanation:

(a)

3(2³+2(-1))+2+(2)(-1)

3(8-2)+2-2

3(6)+0

18

(b)

2((-2)(-1)-1)+4-((-2)²+(-2)(-1))

2(2-1)+4-(4+2)

2(1)+4-(6)

6-6

0

(c)

3((-3)²-(-3)(-1))+4+(-3)(-1)

3(9-3)+4+3

3(6)+7

18+7

25