Answer: choice (3), x = (2b+7)/(a-b)
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Explanation:
The idea is to get all the x terms to one side (after distributing), then factoring out the common term x, finally divide both sides by (a-b) as shown below
ax-7 = b(x+2)
ax-7 = bx+2b .... distribute
ax-7+7 = bx+2b+7 ... add 7 to both sides
ax = bx+2b+7
ax-bx = bx+2b+7-bx ... subtract bx from both sides
ax-bx = 2b+7
(a-b)x = 2b+7 .... factor out the GCF x
x = (2b+7)/(a-b) ... divide both sides by (a-b)
We have all of "2b+7" over "a-b" as one big fraction. This is what choice (3) is showing.
