you can use the formula "<em>Cross method" </em> in which the last number of the equation is the sum of 2 number multiplication that also sums the 2nd num of the equation.
so it becomes
(x +6)(x +7)
WHY?
Bcs when u multiply 6 x 7 = 42 ( the last number of the equation)
when u sum 6 + 7 = 13 ( the 2nd number of the equation)
