Answer:
A. 9x^4 and 3x^5y
Step-by-step explanation:
there are two ways to solve this:
first way:
You can solve this my substituting numbers for x and y in this case i used 2 for x and 3 for y and see which one is equal to the original equations
the second way is the regular way
when you add or subtract numbers with variables and exponents you want to add the constants and add the exponents in this case
is the same as
=
and you can do the same process for subtraction
= 
Set it up like a regular equation. I used:

As you can see, however, I inserted the "less than" symbol rather than the equal sign because values greater than a certain value can also equal "x". Solve it like a normal equation and you will arrive at:
<u>
</u>

This means that, as long as x is greater than 45, "6x" will be greater than "3x+135". Thus, if you bring 46 students, the Science Center will cost less.
Answer:
First then second answer below
Step-by-step explanation:
-x+y 4
-1/-1=1 x=1 y=1
y/1=1/1+4/1
y=1x+4
-x+7y 21
-1/-1=1
7y/7=1/7+21/7
y=1/7x+3
Πr^2=area 9=r 9^2=81π=254.47
-3x-5+2x=6
2x-3x-5=6
-1x-5=6
-x-5=6
-x=11
x=11
an equivilent equaiton is x=11