10(1+3x)=-20 and -5x-8(1+7x)=-8 with steps

(1)

10(1+3x)=-20

Cross multiply.

10+30x=-20

Isolate x on one side. So you would subtract 10 on each side. and one side will cross each other out. leaving you with,

30x=-20-10

Subtract 10 from -20.

30x=-30

Divide each side by 30 to get x.

30x÷30=-30÷30

Therefore,

x=-1

(2)

-5x-8(1+7x)=-8

Cross multiply -8(1+7x)

-5x-8-56x=-8

Isolate all x's on one side. So you would add 8 on each side. and one side will cross each other out. leaving you with,

-5x-56x=-8+8

Add 8 to -8.

-5x-56x=0

Subtract -56x from -5x

-61x=0

Divide each side by -61

-61x÷-61=0÷-61

Therefore,

x=0

problem:

f(x) = - 2/3x + 5; f(5/2)

substitute 5/2 in for x:

f(5/2) = -2/3(5/2) + 5

simplify the right side:

f(5/2) = -5/3 + 5

f(5/2) = 10/3

f(5/2) = 10/3

i hope this !

step-by-step explanation: