Solve for y. A triangle's three angle measures are: 80 degrees, y degrees, and unknown. The exterior angle next to unknown, measures (3y-22) degrees.

Assumptions: x = unknown angle, sum of angles in a
triangle is 180, sum of adjacent angles is 180.

The first
step is to set up 2 equations

1. 80 + y +x =
180

2. x+(3y-22)=180

Now
simplify each equation independantly

For equation 1,
subtract 80 from both sides.

1. x + y =
100

For equation 2, remove parenthesis and add 22 to both
sides.

2. x + 3y = 202

Now
place bothe equations one above the
other

x+y=100

x+3y=202

Now
multiply the first equation by -1 on both
sides

-x-y=-100

x+3y=202

Now
add like terms from eq 1 and eq
2

0+2y=102

Divide new eq by 2
on each side

2y/2 =
102/2

y=51