These questions are some teacher's hairbrained idea that we can keep the students current on algebra while learning geometry. While there are many ways to combine algebra and geometry, this way is awful.
Triangle angles add to 180 degrees. Geometry done.
Equation that models ...:
2x + 5 + 3x + 7 + 2x = 180
Solving,
7x + 12 = 180
7x = 168
x = 168/7 = 24
Answer: x=24
A=2x+5=2(24)+5= 53°
B = 3x+7 = 3(24) + 7 = 79°
C = 2x = 48°
Answer: A=53°, B=79°, C=48°