Question

10x+10=100

5x-10=10

2x=100

Answer 1

10x=100-10
10x=90
x=90/10
x=9

5x=10+10
5x=20
x=20/5
x=4

x=100/2
x=50

Answer 2

$10x+10=100 \\ 10x=100-10 \\ 10x=90 \\ x=90/10 \\ x=9 \\ \\ 5x-10=10 \\ 5x=20 \\ x=20/5 \\ x=4 \\ \\ 2x=100 \\ x=100/5 \\ x=50$