The ANSWER IS A
A) 7x+3y=15
Just plug in x = t
f(t) = 9 -2t.
The exterior angle of any chosen angle of a triangle is simply the linear pair (complement). Therefore, you can find the angles by subtracting the chosen angle from 180.
2(21x − 7) + 4(3x + 2) = 6(2x + 9) + 3
42x - 14 + 12x + 8= 12x + 54 + 3
54x - 6= 12x + 57
54x=12x + 63
42x=63
x= 63/42
x= 3/2
