Lilly likes to collect records. Last year she had 15 records in her collection. Now she has 18 records. What is the percent increase of her collection?

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180

y > 1/3x

y < = -x + 4

hope this : )