Question

a) -12.(x-5)+7(3-x)=15

b) 30.(x+2)-6.(x-5)-24.x=100

Answer 1

\(-12\left(x-5\right)+7\left(3-x\right)=15\)

\(-12x+60+21-7x=15\)

\(-12x-7x=15-60-21\)

\(-19x=-66\)

\(x=\frac{66}{19}\)

Vây....

b)

Answer 2

a) -12.(x-5)+7(3-x)=15

<=> - 12x + 60 + 21 - 7x = 15

<=> 12x + 7x = 60 + 21 - 15

<=> 19x = 66

<=> x = \(\frac{66}{19}\)

Vậy x = \(\frac{66}{19}\)

b) 30.(x+2)-6.(x-5)-24.x=100

<=> 30x + 60 - 6x + 30 - 24x = 100

<=> 0x = 10(vô lí)

VẬY x = \(\varnothing\)

Answer 3

-12.(x-5)+7(3-x)\(=\)15

\(\Leftrightarrow\) -12x+60+21-7x\(=\)15

-19x+81=15

-19x=15-81

19x=66

x=66/19