42=-1(1+x)-7(x+3)

Solution for 42=-1(1+x)-7(x+3) equation:

Simplifying
42 = -1(1 + x) + -7(x + 3)
42 = (1 * -1 + x * -1) + -7(x + 3)
42 = (-1 + -1x) + -7(x + 3)

Reorder the terms:
42 = -1 + -1x + -7(3 + x)
42 = -1 + -1x + (3 * -7 + x * -7)
42 = -1 + -1x + (-21 + -7x)

Reorder the terms:
42 = -1 + -21 + -1x + -7x

Combine like terms: -1 + -21 = -22
42 = -22 + -1x + -7x

Combine like terms: -1x + -7x = -8x
42 = -22 + -8x

Solving
42 = -22 + -8x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '8x' to each side of the equation.
42 + 8x = -22 + -8x + 8x

Combine like terms: -8x + 8x = 0
42 + 8x = -22 + 0
42 + 8x = -22

Add '-42' to each side of the equation.
42 + -42 + 8x = -22 + -42

Combine like terms: 42 + -42 = 0
0 + 8x = -22 + -42
8x = -22 + -42

Combine like terms: -22 + -42 = -64
8x = -64

Divide each side by '8'.
x = -8

Simplifying
x = -8