Question 22620
Start with A + B = 180 degrees  (A means...the measure of angle A)

A = 4B-10  "The measure of angle A is (=) 4 times the measure of angle B (4B) less 10 degrees (-10)".  Substitute this equation for A into the above equation for A + B = 180.

(4B-10) + B = 180  Simplify and solve for B
5B - 10 = 180  Add 10 to both sides.
5B = 190 Divide both sides by 5.
B = 38 degrees.

Check:

A = 4(38)-10 = 152 - 10 = 142 degrees.
 A + B = 142 + 38 = 180 degrees.