А) -7х = -21; Б) 4х + 3 = -17; Г) -5х + 9 = 2х + 3 д) 4\7х + 1 3\7 = 6\7х - 5 5\7 ///...

А)

-7x = -21 :(-7)

x=3

Б)

4x+3=-17

4x=-20 :4

x=5

Г)

-5x+9=2x+3

-5x-2x=3-9

-7x=-6 :(-7)

$x=\frac{-6}{-7} =\frac{6}{7}$

Д)

$\frac{4}{7} x+1\frac{3}{7} =\frac{6}{7} -5\frac{5}{7}\\\frac{4}{7} x=\frac{6}{7} -5\frac{5}{7} -1\frac{3}{7} \\\\\frac{4}{7} x=\frac{6}{7} -\frac{40}{7} -\frac{10}{7} \\\frac{4}{7} x=\frac{6-40-10}{7} \\\frac{4}{7} x=\frac{-44}{7} \\4x=-44\\x=-11$

Е)

4x-(3-2x)=-(13-5x)

4x-3+2x=-13+5x

4x+2x-5x=-13+3

x=-10