Can some one help with the following please…???

5. 8

6. 18

Step-by-step explanation:

5.

a(a^2 + a - 1) + 7 =

= a^3 + a^2 - a + 7

For a = -1,

= (-1)^3 + (-1)^2 - (-1) + 7

= -1 + 1 + 1 + 7

= 8

6.

2ab(a + b) - 3ab(a - b) =

= 2a^2b + 2ab^2 - 3a^2b + 3ab^2

= -a^2b + 5ab^2

For a = 1 and b = 2,

= -(1)^2(2) + 5(1)(2)^2

= -1(2) + 5(4)

= - 2 + 20

= 18

Step-by-step explanation:

a(a^2 + a -1) +7

a^3+a^2-a+7

f(-1)=(-1)^3+(-1)^2-(-1)+7

f(-1)=-1+1+1+7

f(-1)=0+1+7

f(-1)=8

2ab(a+b)-3ab(a-b)

2a^2*b+2ab^2-3a^2*b+3ab^2

−a^2*b+5ab^2

when a=1 and b=2

−a^2*b+5ab^2

−(1)^2*2+5*1*2^2

-1*2+5*1*4

-2+5*4

-2+20

18