All degrees (angles) in a triangle add up to 180°. So we can set the sum of the three angles equal to 180°: (x-5)+(3x+25)+x = 180 5x + 20 = 180 5x = 160 x = 32° But it asked for m<F, so plug in for x: m<F = x - 5 = 32 - 5 = 27°
3.9 and 5.3, when rounded off and mult. together, produce the product 20. Thus, the decimal point must follow the first two digits of your answer, whether estimate or "exact."
; otherwise 
is undefined as long as we're only looking for real solutions.
