-3(2-7k)-2(5k-8)=21

Solution for -3(2-7k)-2(5k-8)=21 equation:

Simplifying
-3(2 + -7k) + -2(5k + -8) = 21
(2 * -3 + -7k * -3) + -2(5k + -8) = 21
(-6 + 21k) + -2(5k + -8) = 21

Reorder the terms:
-6 + 21k + -2(-8 + 5k) = 21
-6 + 21k + (-8 * -2 + 5k * -2) = 21
-6 + 21k + (16 + -10k) = 21

Reorder the terms:
-6 + 16 + 21k + -10k = 21

Combine like terms: -6 + 16 = 10
10 + 21k + -10k = 21

Combine like terms: 21k + -10k = 11k
10 + 11k = 21

Solving
10 + 11k = 21

Solving for variable 'k'.

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

Add '-10' to each side of the equation.
10 + -10 + 11k = 21 + -10

Combine like terms: 10 + -10 = 0
0 + 11k = 21 + -10
11k = 21 + -10

Combine like terms: 21 + -10 = 11
11k = 11

Divide each side by '11'.
k = 1

Simplifying
k = 1