Triangle ABC
A= (4y + 10)
C= (3x)
B= 75
What is y?

y = 5

Explanation:

Given parameters:

    Angle A = 4y + 10

    Angle B  = 75

    Angle C = 3x

Unknown:

Value of y = ?

Solution:

The triangle is an isosceles triangle with two equal sides and angles.

  Here;

                 3x  = 75

                    x  =   = 25°

In a triangle the sum of angles is 180°, so;

           4y + 10 + 75 + 3(25) = 180

            4y + 160 = 180

            4y  = 180 - 160

            4y  = 20

              y = 5