Lallenge Isabel tried to evaluate an expression step by step.
(2+8) +8
=2 + (8 +8) Step 1
=2 +0
Step 2
Find isabel mistake

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

1/800 is the right answer