The first expression is (x + 3)(x + 4)
To apply the distributive property, we would multiply each term in the first bracket by each term in the second bracket. Thus, we have
x * x + x * 4 + 3 * x + 3 * 4
x^2 + 4x + 3x + 12
= x^2 + 7x + 12
For the second expression,
(x - 3)(x + 4)
x * x + x * 4 + - 3 * x + - 3 * 4
x^2 + 4x - 3x - 12
= x^2 + x - 12
For the third expression,
(x - 4)(x - 3)
x * x + x * - 3 + - 4 * x + - 4 * - 3
x^2 - 3x - 4x + 12
x^2 - 7x + 12
For the fourth expression,
(x - 4)(x + 3)
x * x + x * 3 + - 4 * x + - 4 * 3
x^2 + 3x - 4x - 12
x^2 - x - 12