-(3+r)+3(1+r)=10

Solution for -(3+r)+3(1+r)=10 equation:

Simplifying
-1(3 + r) + 3(1 + r) = 10
(3 * -1 + r * -1) + 3(1 + r) = 10
(-3 + -1r) + 3(1 + r) = 10
-3 + -1r + (1 * 3 + r * 3) = 10
-3 + -1r + (3 + 3r) = 10

Reorder the terms:
-3 + 3 + -1r + 3r = 10

Combine like terms: -3 + 3 = 0
0 + -1r + 3r = 10
-1r + 3r = 10

Combine like terms: -1r + 3r = 2r
2r = 10

Solving
2r = 10

Solving for variable 'r'.

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

Divide each side by '2'.
r = 5

Simplifying
r = 5