3(x^2+5)=42

Solution for 3(x^2+5)=42 equation:

Simplifying
3(x2 + 5) = 42

Reorder the terms:
3(5 + x2) = 42
(5 * 3 + x2 * 3) = 42
(15 + 3x2) = 42

Solving
15 + 3x2 = 42

Solving for variable 'x'.

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

Add '-15' to each side of the equation.
15 + -15 + 3x2 = 42 + -15

Combine like terms: 15 + -15 = 0
0 + 3x2 = 42 + -15
3x2 = 42 + -15

Combine like terms: 42 + -15 = 27
3x2 = 27

Divide each side by '3'.
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}