Question 1067765
(5+x)*(10+x) = 126
rewrite:
(x+5)(x+10) = 126
x^2+15x+50 = 126
x^2+15x-76 = 0
(x-4)(x+19) = 0
split in two:
x-4 = 0 or x+19 = 0
x = 4 or x = -19
We are not looking for a negative number, so let's set the -19 aside and try the 4:
(5+4)(10+4) = 126
9*14 = 126 Correct
:
John