Answer:
x = 5
Step-by-step explanation:
Geometry Theory
This question deals with a right-angled triangle. The sum of the angles in a triangle is equal to 180 degrees. A right angle is equal to 90 degrees which means that the other two angles must equal to 90 degrees as well.
Algebra
Form the equation.
( 7x + 1 ) + 54 + 90 = 180;
Subtract 90 from both sides.
7x + 1 + 54 + 90 - 90 = 180 - 90;
7x + 1 + 54 = 90;
Simplify left-hand side.
7x + 55 = 90;
Subtract 55 from both sides.
7x + 55 - 55 = 90 - 55;
7x = 35;
Divide both sides by 7.
x = 35 / 7;
x = 5;