Help please i need the answer by tonight for my grades

Answer:
X equals negative 11
Step-by-step explanation:
The angles in a triangle add up to be 180 degrees, and we already have 80 as one angle and 60 as the other. That equals 140 degrees. But now we have x+51. That would equal 191 degrees, so 191-180=11, so x= -11
Answer:
x=-11
What we know=
Angles A'=x+51
Angle B=60
Angle C=80
Angle B' and C'=?
Due to the vertically opposite angle rule, we know angle B' and C' are the same as angle B and C.
So, angle B' is 60 degrees. Angle C' is 80 degrees.
We can add them together to get 140 degrees.
So we have 140, x+51. We can make an equation.
[tex]180=140+51+x[/tex] We can combine like terms (140 and 51) to get 191
A triangle only adds up to 180 degrees. So now you can subtract 180-191=to get x.