The sum of the measures of angle x and y is 90. If the measures of angle x is 30 less than twice the measures of angle y what is the measure of angle x?

First set up your two equations:

x + y = 90

x = 2y - 30

Then substitute what x equals in the second equation into the first equation:

(2y - 30) + y = 90

Now solve for y:

3y - 30 = 90

3y = 120

y = 40

Then use y = 40 and substitute the value for y into one of your original equations and solve for x. I'll choose the first one, but either one will work.

x + 40 = 90

x = 50

So your solution is x = 50 and y = 40