First, simplify.
Solve the left side. First, distribute 3 to all terms within the parenthesis
3(2x + 5) = 3(2x) + 3(5) = 6x + 15
Combine the terms on the right side
3x + 4x = 7x
Set them equal to each other
6x + 15 = 7x
Isolate the x. Subtract 6x from both sides
6x (-6x) + 15 = 7x (-6x)
15 = 7x - 6x
SImplify. Combine like terms
15 = x
15 is your solution for x
hope this helps