Đáp án:
ở dưới
Giải thích các bước giải:
a) -5.(-x + 7) - 3.(-x - 5) = -4.(12 - x ) + 48
$5x-35+3x+15=-48+4x+48_{}$
$5x+3x-4x=-48+48-15+35_{123}$
$4x=20_{}$
$x=5_{}$
b) -2.(15 - 3x) - 4.(-7x + 8) = -5 - 9.(-2x + 1)
$-30+6x+28x-32=-5+18x-9_{}$
$6x+28x-18x=-5-9+32+30_{}$
$16x=48_{}$
$x=3_{}$
c) 7.(-x - 7) - 5.(-x - 3) = 12.(3 - x)
$-7x-49+5x+15=36-12x_{}$
$-7x+5x+12x=36+49-15_{}$
$10x=70_{}$
$x=7_{}$
d) 5.(-3x - 7) - 4.(-2x - 11) = 7.(4x + 10) + 9
$-15x-35+8x+44=28x+70+9_{}$
$-15x+8x-28x=70+9-44+35_{}$
$-35x=70_{}$
$x=-2_{}$