You're original equation has a -81, so the factored form will have to have a positive and negative multiplying one another to achieve that...
f(x) = x(x + 9)(x - 9)
In order to form a triangle, the third side must be at least greater than the difference of the other two sides
4 - 3 = 1 So the third side must be greater than 1 foot and the third side must be less than the sum of the other two sides
4 + 3 = 7 So, the third side must be less than 7
1 < third side < 7
M< 6 = m< 7 (vertical angles)
11x + 8 = <span>12x – 4
12x - 11x = 8 + 4
x = 12
so
m< 6 = </span>11x + 8
m< 6 = 11(12) + 8
m< 6 = 132 + 8
m< 6 = 140
m<4 = 180 - m<6
m<4 = 180 - 140
m<4 = 40
answer
<span>m<4 = 40</span>
A B C D E represent the subjects
A+A1
A+B2
A+C3
A+D4
A+E5
B+B6
B+C7
B+D8
B+E9
C+C10
C+D11
C+E12
D+D13
D+E14
E+E15
15 combos