Solve for r
r=-7
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15-20r+7r=106
Use the distributive property to multiply -5 by -3+4r.
15-13r=106
Combine -20r and 7r to get -13r.
-13r=106-15
Subtract 15 from both sides.
-13r=91
Subtract 15 from 106 to get 91.
r=\frac{91}{-13}
Divide both sides by -13.
r=-7
Divide 91 by -13 to get -7.
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