105=-7(1-4r)

Solution for 105=-7(1-4r) equation:

Simplifying
105 = -7(1 + -4r)
105 = (1 * -7 + -4r * -7)
105 = (-7 + 28r)

Solving
105 = -7 + 28r

Solving for variable 'r'.

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

Add '-28r' to each side of the equation.
105 + -28r = -7 + 28r + -28r

Combine like terms: 28r + -28r = 0
105 + -28r = -7 + 0
105 + -28r = -7

Add '-105' to each side of the equation.
105 + -105 + -28r = -7 + -105

Combine like terms: 105 + -105 = 0
0 + -28r = -7 + -105
-28r = -7 + -105

Combine like terms: -7 + -105 = -112
-28r = -112

Divide each side by '-28'.
r = 4

Simplifying
r = 4