Simplify. radical expression's.

√18

If angle ywz = 17, what is angle wxy? ok so i'm confused on this because the triangles are congruent so that means they have the same measurement which would make wxy=17, but don't all triangles have total measures of 180 degress? ?me.

7x+8y=-18, 4x-9y=-3 solve the system of equations

The length of a rectangle plus its width is 25 cm. the area is 156 square cm. what are the length and width of the rectangle? separate the answers with a comma.