Answer:

Step-by-step explanation:
Given
The attached triangle
Required
Find y
The attached triangle is isosceles; so:

Also, we have:
--- angles in a triangle
Substitute: 

Collect like terms


Answer:
422 in.2
Step-by-step explanation:
Substitute the measurements of the rectangular prism into the formula SA = 2(lw) + 2 (lw) + 2(lh): 2(13)(7) + 2(6)(7) + 2(13)(6) = 422 in2.
Answer: He bought 8 quarts
Step-by-step explanation:
There are 4 quarts in a gallon so if you multiply 4 by 2 then you get 8,
Take the root of both sides, and solve.
x = 2i sqrt 2, -2i sqrt 2.