Which of the following is a flat surface that extends infinitely, has length and width, but does not have depth?

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10

Find the perimeter of the triangle with vertices  d(3, 4),  e(8, 7), and  f(5, 9). do not round before calculating the perimeter. after calculating the perimeter, round your answer to the nearest tenth.  

Qrst is a parallelogram. determine the measure of ∠q pls