I'm thinking this is what the problem looks like:

. The first thing to do is to move the

over to the other side because it has a common denominator with the other side. Doing that and at the same time combining them over their common denominator looks like this:

. The best way to solve for x now is to cross-multiply to get 3(4-x)=-4(x-4). Distributing through the parenthesis is 12 - 3x = -4x + 16. Solving for x gives us x = 4. Of course when we sub a 4 back in for x we get real problems, don't we? Dividing by zero breaks every rule in math that there ever was! So, yes, the solution is extraneous.
Answer:
22
Step-by-step explanation:
The preimeter is adding all sides together. I took 154-55 twice sense we have four sides of a rectangle and two are lengths. after that i got 44. I then just remembered we had two sides left so divided that by 2 and got 22
Answer:
6 donuts
Step-by-step explanation:
first divide the cost of the donuts by the amount of donuts per box
6 donuts:
2.10 ÷ 6 = .35 per donut
12 donuts
5.40 ÷ 12 = .45 per donut
18 donuts
7.20 ÷ 18 = .40 per donut
24 donuts
12 ÷ 24 = .50 per donut