First we will need to multiply out our brackets:
10(2 + x) = 15(x - 1) + 5
20 + 10x = 15x -15 + 5
Next we will add our like terms. We will add 10x and 15x because they are both coefficients of x.
20 + 10x - 15x = -15 + 5
10x - 15x = -20 - 15 +5
-5x = -30
x = 6