2.89-2.7r-.8r=-1.31

Solution for 2.89-2.7r-.8r=-1.31 equation:

Simplifying
2.89 + -2.7r + -0.8r = -1.31

Combine like terms: -2.7r + -0.8r = -3.5r
2.89 + -3.5r = -1.31

Solving
2.89 + -3.5r = -1.31

Solving for variable 'r'.

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

Add '-2.89' to each side of the equation.
2.89 + -2.89 + -3.5r = -1.31 + -2.89

Combine like terms: 2.89 + -2.89 = 0.00
0.00 + -3.5r = -1.31 + -2.89
-3.5r = -1.31 + -2.89

Combine like terms: -1.31 + -2.89 = -4.2
-3.5r = -4.2

Divide each side by '-3.5'.
r = 1.2

Simplifying
r = 1.2