
Andrew R. answered 05/01/13
Full-Time Math Teacher, Part-Time Tutor, Maximum Results
9t+6/t(t+3) = 7/(t+3)
(9t+6)(t+3)=7t(t+3) (Cross multiply the proportion)
9t+6=7t (divide (t+3) from both sides)
2t+6=0 (subtract 7t from both sides)
2t=-6 (subtract 6 from both sides to solve for t)
t=-3 (answer)
However, notice that when t=-3 the proportion is undefined on both sides, because when t=-3 the denominator is 0.