Well the sum is 15+6=21. then you must do 81-21=60. So your answer must be t=60.
Answer:
A(3) = -6 + (3 - 1) (5)
-6 + (2)(5)
-6 + (10)
4
A(4) = -6 + (4 - 1) (5)
-6 + (3)(5)
-6 + 15
9
A(10) = -6 + (10 - 1) (5)
-6 + (9)(5)
-6 + 45
39
X^2-11x+28=0
(x-7)(x-4)=0
x-7=0
x=7
x-4=0
x=4
31
since A = 1/2 b h, and the A is 279 and the height is 18, we can plug them in and solve for b.
