4x * (x + 3) - (2x - 5)(2x + 5) = 48;
4x^2 + 12x - (4x^2 - 25) = 48;
4x^2 + 12x - 4x^2 + 25 = 46;
4x^2 - 4x^2 + 12x = 46 - 25
12x = 21;
x = 21/12;
x = 7/6;
x = 1 1/6.
4x * (x + 3) - (2x - 5)(2x + 5) = 48;
4x^2 + 12x - (4x^2 - 25) = 48;
4x^2 + 12x - 4x^2 + 25 = 46;
4x^2 - 4x^2 + 12x = 46 - 25
12x = 21;
x = 21/12;
x = 7/6;
x = 1 1/6.