Answer: 17
21-4=17
4+17=21
21+17=38 and so on..
So if you subtract the 0 out from the left side, the equation is now

. Since a x is common in both of the terms on the left side, you can factor it out, now making the equation look like

. When factoring, each of the separate things (x and (x-3)), must equal zero while the other one doesn't matter. So in order for the equation to be 0, the only potential options for x is 0 and 3. Therefore x=0 and x=3 are the two solutions
If you would like to know which of the following steps should be performed to eliminate variable d first, you can find this using the following steps:
equation a: 2c = d - 8 /*(-3)
equation b: c = 3d + 8
__________________
-6c = -3d + 24
c = 3d + 8
__________________
-6c + c = -3d + 24 + 3d + 8
-5c = 32
5c = -32
c = -32/5
<span>The correct result would </span>be: <span>multiply equation a by −3.</span>
2. Put it in your own words
You're phrasing it, so it shouldn't be much longer than the actual line. It should just be your interpretation.