Question

How do you solve
10x + 7 = 2(5x - 8) and
3(3b + 1) = 2(7b - 21)?

Answer 1

  10x+7=2(5x-8)
  10x+7=10x-16
       +16      +16
10x+23=10x
-10x       -10x
        23=0

3(3b+1)=2(7b-21)
    9b+3=14b-42
       +42       +42
  9b+45=14b
  -9b       -9b
        45=5b
          9=b