Ruben bought 6 comic books for $21. what was the cost for 1 comic book

In the proof of the triangle angle sum theorem, you must draw an auxiliary line. which construction must you use to draw this line?

Solve the equation x/4 - 5= -8 -27 -12 -7 12

Isabel graphed the following system of equations. 2x – y = 6 y = -3x + 4 she came up with the solution (2,-2). what were the 3 steps she did to get that solution? (make sure they are in the correct order)