(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
