Answer:
x = 5
Step-by-step explanation:
Angles in a triangle add up to equal 180
Hence, 10x - 1 + 78 + 53 = 180
( Note that we just created an equation that we can use to solve for x )
We now solve for x using the equation we created
10x - 1 + 78 + 53 = 180
Combine like terms
10x + 130 = 180
Subtract 130 from both sides
10x = 50
Divide both sides by 10
x = 5
