Question

tìm X biết:

a,-7.(5-X)-2.(X-10)=15

b,10.(X-7)-8.(X+5)=6.(-5)+24

Answer 1

a  -7.(5-x) -2.(x-10)=15

= -35+7x-2x+20=15=5x=30

5x=30

x=6

b 10.(x-7)-8.(x+5)=6.(-5)+24

=10x-70-8x-40= -30+24

=10x-8x           = -30+24+70+40

2x                     = 104

x                       = 104:2

x                       = 52

Answer 2

\(a)-7\left(5-x\right)-2\left(x-10\right)=15\)

\(\Rightarrow-35+7x-2x+20=15\)

\(\Rightarrow-35+20+7x-2x=15\)

\(\Rightarrow-15+5x=15\)

\(\Rightarrow5x=30\Rightarrow x=6\)

\(b)10\left(x-7\right)-8\left(x+5\right)=6\left(-5\right)+24\)

\(\Rightarrow10x-70-8x-40=-30+24\)

\(\Rightarrow10x-8x-70-40=-6\)

\(\Rightarrow2x-110=-6\)

\(\Rightarrow2x=104\Rightarrow x=52\)

Vậy\(a)x=6b)x=52\)