Answer:

Step-by-step explanation:

Expand the brackets.

Multiply.

C - remember the vertical line test determines if something is a function. A function has 1 x value for 1 y value. A B and D have more than one y value for a given x value.
Answer:
x = 8
Step-by-step explanation
Complimentary angles have a sum of 90*. Thus when adding the two equations together, we must get 90*.
7x + 17 + 3x - 7 = 90 Combine like terms
10x + 10 = 90 Subtract 10 on both sides
10x = 80 Divide both sides by 10
x = 8
it is a iscoceles obtuse triangle
hope this helped:)