3r+21=-4r

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Solution for 3r+21=-4r equation:


Simplifying
3r + 21 = -4r

Reorder the terms:
21 + 3r = -4r

Solving
21 + 3r = -4r

Solving for variable 'r'.

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

Add '4r' to each side of the equation.
21 + 3r + 4r = -4r + 4r

Combine like terms: 3r + 4r = 7r
21 + 7r = -4r + 4r

Combine like terms: -4r + 4r = 0
21 + 7r = 0

Add '-21' to each side of the equation.
21 + -21 + 7r = 0 + -21

Combine like terms: 21 + -21 = 0
0 + 7r = 0 + -21
7r = 0 + -21

Combine like terms: 0 + -21 = -21
7r = -21

Divide each side by '7'.
r = -3

Simplifying
r = -3

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