10.(x-7)-10=20
10.(x-7)=20+10
10.(x-7)=30
x-7=30/10
x-7=3
x=7+3
x=10
Ta có 10.(x-7)-10=20
⇔ 10 ( x - 8 ) = 20
⇔ x - 8 = 2
⇔ x = 10
Vậy x = 10
@@ Học tốt
10(x - 7) - 10 = 20
⇔10x - 70 -10 = 20
⇔10x = 20 + 70 + 10
⇔10x = 100
⇔x = 10
Vậy x = 10.
10.(x-7)-10=20
=>10.(x-7)=20+10
=>10.(x-7)=30
=>x-7=30:10
=>x-7=3
=> x=3+7
=>x=10
10.(x-7)-10=20
10.(x-7) = 20+10
10.(x-7) = 30
x-7 = 30:10
x-7 = 3
x = 3+7
x = 10