10r^2-21=-4+6

Solution for 10r^2-21=-4+6 equation:

Simplifying
10r2 + -21 = -4 + 6

Reorder the terms:
-21 + 10r2 = -4 + 6

Combine like terms: -4 + 6 = 2
-21 + 10r2 = 2

Solving
-21 + 10r2 = 2

Solving for variable 'r'.

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

Add '21' to each side of the equation.
-21 + 21 + 10r2 = 2 + 21

Combine like terms: -21 + 21 = 0
0 + 10r2 = 2 + 21
10r2 = 2 + 21

Combine like terms: 2 + 21 = 23
10r2 = 23

Divide each side by '10'.
r2 = 2.3

Simplifying
r2 = 2.3

Take the square root of each side:
r = {-1.516575089, 1.516575089}