Question

1,tìm x

a,3.(x-5)-4.(x-3)=-12

b,(x-3).(2.y+1)=7

c,20-(x-15)=x-15

d,-(5+x)-120=-15

Answer 1

d, x=-110

Answer 2

\(a,3\left(x-5\right)-4\left(x-3\right)=-12\)

\(\Leftrightarrow3x-15-4x+12=-12\)

\(\Leftrightarrow-x=-9\)

\(\Leftrightarrow x=9\)

Vậy x=9

Answer 3

\(c,20-\left(x-15\right)=x-15\)

\(\Leftrightarrow20-x+15=x-15\)

\(\Leftrightarrow2x=50\)

\(\Leftrightarrow x=25\)

Vậy x=25