Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Find y
The attached triangle is isosceles; so:

Also, we have:
--- angles in a triangle
Substitute: 

Collect like terms


We have the expression:

And want to evaluate in y=5, this means we have to replace y in the expression for 5 and calculate the value of the expression, so:

The expression is 30 when y=5.
Answer:
there is no picture...
Step-by-step explanation:
Answer:
x=8a
Step-by-step explanation:
(3/a) x - 4 = 20
add 4 to both sides
(3/a) x = 24
Divide by 3/a
x = 24 / (3/a)
Use KCF (keep change flip)
x = (24/1) x (a/3)
x = 24a / 3
simplify
x = 8a