Answer
$4x + 10$
Work Step by Step
In step 1, foil both sets of parentheses. In steps 2 and 3, simplify the problem by adding and subtracting like terms. Then we will have the final answer.
$(x+4)(x+3) - (x+1)(x+2)$
$= x^{2} + 7x + 12 - (x^{2} + 3x + 2)$
$= x^{2} + 7x + 12 - x^{2} - 3x - 2$
$= 4x + 10$