Question

The area of a rectangular field is given by the trinomial t^2-4t-45. The length of the rectangle is t+5. What is the expression for the width of the field?

A. t-9
B. t-5
C. t-11
D. t-7

Answer 1

we know that
[area of rectangle]=L*W

where 
L=is the length 
W=is the wide
Area=t²-4t-45
L=t+5

so

t²-4t-45=(t+5)*W
t²-4t-45=(t+5)*(t-9)
(t+5)*(t-9)=(t+5)*W---------> W=(t-9)

the answer is 
W=(t-9)