12. It's similar to having an infinite number of solutions because there isn't a specific solution to answer the question.
13. For the equation 0.9x + 5.1x - 7 = 2(2.5x-3), there is only one solution and it is x=1
14. The error that your friend made was that she added extra 16x to the equation. the correct answer is that there is no solution.
16. the equation 6 (x+2)= 5 (x+7) has only one solution. it is x=3.
sorry i wasn't able to answer the other 3,
by the way you don't need to send money, because we are here to help
Answer:

You have the side lengths of the two legs, n and n.
Then, using the pythagorean theorem you have to find the length of the third side:

where c is the third side
the answer is 4.23×10×10×10=4230
9514 1404 393
Answer:
66 m
Step-by-step explanation:
The perimeter is the sum of the measures of <em>all</em> of the sides. There are two side measures that are missing from the diagram.
The missing horizontal measure is ...
17 m - 8 m = 9 m
The missing vertical measure is ...
16m -7 m = 9 m.
If you add these to the sum you already calculated, you will get the correct answer:
48 m + 9 m + 9 m = 66 m . . . perimeter of the figure
_____
If you're paying attention, you see that the sum of the measures of the two shorter horizontal segments is the same as the measure of the longer horizontal segment. Likewise, the sum of the measurements of the two shorter vertical segments is the same as that of the longer vertical segment.
In other words, the perimeter of this (and any) L-shaped figure is the same as the perimeter of a rectangle having the same horizontal and vertical dimensions as the long sides of the figure.
P = 2(17 m +16 m) = 2(33 m) = 66 m
The answer is going to be 3,495