The second one is the write answer
The side of a square would be 5 because the square root of 25 is 5.
if we look on one side, we already have one measurement. 4 cm. ok, that's the measurement on that side. look to the left now. that other side is also the same length, so we take that number and multiply it be 2 to get

Wait! we're not done yet. look at the top. do you see the 3? well that's the width for the top of the rectangle. the bottom must be the same to right? so we get

add both equations and you get

The answer is 14cm! Don't forget to label. ;)
Answer:
I agree with the student's answer. "x" cannot be -2 because then it would make -20 which is not equal to 20:
5(-2)(2) = ?
-10 x 2 = ?
? = -20
-20 ≠ 20
Step-by-step explanation:
Justificaiton:
5(x)(2) = 20
10(x) = 20
10/10(x) = 20/10
x = 2
Second Justification:
5(x)(2) = 20
5/5(x)(2) = 20/5
2x = 4
2x/2 = 4/2
x = 2
No solution would mean that there is no answer to the equation. It is impossible for the equation to be true no matter what value we assign to the variable. Infinite solutions would mean that any value for the variable would make the equation true. :)