Answer:
178 - 3x.
Step-by-step explanation:
The three angles in a triangle add up to 180 degrees so an expression for the third angle is:
180 - (x + 9) - (2x - 7)
Distributing the negative over the parentheses, we have
180 - x - 9 - 2x + 7
= 180 - 9 + 7 - x - 2x
= 180 - 2 - 3x
= 178 - 3x (answer).
Answer:
178-3x
Step-by-step explanation:
The three angles of a triangle add to 180 degrees
<1 +<2 +<3 = 180
Let angle 1 = x+9 and <2 =2x-7
x+9 + 2x-7 +<3 = 180
Combine like terms
3x+2 +<3 = 180
Subtract 3x from each side
3x-3x+2 +<3 = 180-3x
2+<3 = 180-3x
Subtract 2 from each side
2-2 +<3 = 180-2-3x
<3 = 178 -3x
