Answer:
hi
Step-by-step explanation:
Yes, you made an algebraic error. By multiplying 18 x 4, you messed up on order of operations.
(x+9)(x+2)*4
becomes:
(x^2+11x+18)*4
= 4x^2 + 44x + 72
anyway, this is how I would do this problem:
(x+9)(x+2)(4) = 912
(x+9)(x+2) = 228
x^2 + 11x + 18 = 228
x^2 + 11x - 220 = 0
(x+21)(x-10) = 0
x = -21 or 10
The dimensions can't be negative, so we only use x = 10
The dimensions are then 10+9, 10+2, 4
or 19, 12, 4
Because the number is even, then the number of possible combinations will be: 110/2 = 55 let's consider a simpler example, the number: 10, then we have: 10+0, 9+1, 8+2, 7+3, 6+4, which is equal to 10/2 =5 combinations. Note: We are not considering permutations between the elements of the sum therefore 10+0, 0+10 counts as one combination.
D 2x + 28 = 48
because x + x + 14 + 14 equals the perimeter which is 48
