To use mental math think instead of 81 to 80 and 16 to 10 and subtract that and add the other numbers and subtract that and you will have your answer presto!
the correct answer would be -24x because 9+12 is 21 and 21 - 45 would be -24
Answer:here use
Step-by-step explanation:
Let width be w then the length l = w + 7
Area = w(w + 7) = 120
w^2 + 7w - 120 = 0
w = 8 or -15 (ignore negative)
So w = 8 and l = 8+7 = 15
Length of the diagonal d is calculated using Pythagoras theorem:-
d^2 = 8^2 + 15^2 = 289
diagonal = sqrt 289 = 17 feet (answer)