1) (40+x)*10=800400+10x=80010x=400x=40
2) (x-56)*9=9099x-504=9099x=1413x=157
3) x+x+100=28028/142x+100=20022x=1902x=951
4) 4(3x+4x)+700=70*1612x+16x+700=112028x=420x=15
1) (40+x)*10=800
400+10x=800
10x=400
x=40
2) (x-56)*9=909
9x-504=909
9x=1413
x=157
3) x+x+100=28028/14
2x+100=2002
2x=1902
x=951
4) 4(3x+4x)+700=70*16
12x+16x+700=1120
28x=420
x=15