Example:

This suggests two solutions,
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and

.
However, upon plugging these solutions back into the equation, you get

which checks out, but

does not because

is defined only for

(assuming you're looking for real solutions only). So, we call

an extraneous solution, and the complete solution set (over the real numbers) is

.
Answer:
round it then divide it by 5
Step-by-step explanation:
Ok she can buy 1 ten and 25 ones, 2 tens 15 ones, 3 tens 5 ones, and 35 ones. (Pretty sure)
Here is my process for solving this.
First I drew arrows that indicated I was moving the whole triangle 5 units to the left.
*Look at first attachment*
Then I drew another triangle using those new points. (The new triangle is in pink)
*Look at second attachment*
Then I drew arrows that moved this new triangle 4 units up. (The new arrows are in pink)
*Look at third attachment*
Then I drew the new triangle in blue using the new points.
*Look at fourth attachment*
Then I mirrored / reflected the triangle over the x axis (the horizontal line) In green.
*Look at fifth attachment*
The fifth attachment in green is the final product! Hope that helps.