3x + 9 = 90
3x = 90 - 9 = 81
x = 81/3 = 27
x = 27
Answer:
Step-by-step explanation:
The sum of angles in a triangle is 180 degrees. So the third angle in the triangle is
90+32+a=180
a+122=180
a=58
Now angle x is adjacent to angle a so their sum must equal 180 degrees so
x+58=180
x=122 degrees
The first set of expressions bc 3x is equivalent to 3x and -7y is equivalent to -7y