Answer:
x=7
Explanation:
a triangles Angel's should add up to 180 all together
So, 71+64=135
180-135= 45
now that you have found the missing angle, you need to find x.
set the equation equal to 45:
8x-11=45
now solve:
8x-11 =45
add 11 to both sides to cancel out the negative 11 and try to get x alone:
8x=56
divide 8x by 8 and 56 by 8 to get x alone:
x=7