So our two equations are y=-8x-4 and y=-16, and since in both equations, something equals the same y, those two are the same. So we can combine the two into -16=-8x-4. In the question, they are asking to solve for x. So to do that, you need to isolate your variable. Now for solving algebraic equations, you use reverse PEMDAS (SADMEP), meaning you add 4 to both sides to clear the -4 one the rights side to get -12=-8x. Then you divide both sides by -8 to get 12/8, which simplifies to 3/2.
-5(x+7)<-10. You need to use the distributive property. -5x - 35 < -10. You need to cancel out -35, so you add it to itself, & -10. -5x < 25. You need to divide -5 by itself & 25. x>-5.
