Answer:
x = 18
Step-by-step explanation:
( all traingles have an interior angle that adds up to 180 degree )
equation:
45 + 87 + 3x - 6 = 180
combine like terms:
126 + 3x = 180
subtract 126 from each side:
126 - 126 + 3x = 180 - 126
3x = 54
divide each side by 3:
[tex]\frac{3x}{3} = \frac{54}{3}[/tex]
x = 18
to check, substitute x for 18, both sides of the equation should match
45 + 87 + 3x - 6 = 180
45 + 87 + 3 (18) - 6
180 = 180
