I actually posted this a while ago and it got answerd by a smart person so here's what I understood
the error is that it assumes that √(x²)=x
because if x is negative, it becomes positive
that's how the 2nd line is wrong
the 2nd line is the first wrong step
it goes from 4-9/2+9/2
so it goes from 4-4.5+4.5
notice the part under the parenthsees
√((4-4.5)²)
if we evaluate 4-4.5, we get -0.5
but by squaring it we get 0.5
-0.5+4.5=4, yes
but when we square it we get
0.5+4.5=5, that is how it works
Answer:

Step-by-step explanation:
The question is

collect like terms

Answer:
Y should equal to 4.5
Step-by-step explanation:
Since they are similar triangles and each of the measurements on the second triangle are divided by two you would do the same for y
Get all the m’s together all the 1’s and all the 2’s
Answer:
What I understand is that I need to give someone an exact number so that when 30% is taken, they keep exactly 35,000
To make the statement above true, we would need to divide 35,000 by 7 since the answer would be 10% of the number we need. Once we do this we get 5000 which is 10% now we multiply 5000 by 10 to get 100% and we get 50.000 once we give this amount to the person and 30% is taken away they are left with 35,000