Answer:
x=9
Step-by-step explanation:
Area of a rectangle = length * width
84 = (x-2) * ( x+3); distribute
84 = x²+3x-2x-6; combine like terms and subtract 84 from both sides
0 = x² +x -90
if x= 9 will have 9² +9 -90= 81 +9 -90 = 90-90 = 0 so x=9 works
if x= 10 will have 10² +10 -90 = 100-80= 20 ≠0 so x= 10 does NOT work
if x= -10 and x= -9 will not make sense because we can NOT have a negative measurement
