Write the phrase as an algebraic expression. A number minus three. PLS HEL

Algebraic expression for a number minus three would be

x-3

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

ege

step-by-step explanation:

egge