2x + y = 5
x − 2y = 10
y = 5 − 2x
x − 2(5 − 2x) = 10
x − 10 + 4x = 10
5x − 10 = 10
<em>add 10 to each side</em>
<em>5x-10+10 = 10 + 10</em>
<em>5x=20</em>
5x = 0 <em>this is the error</em>
He needs to add 10 to each side
Answer:
7
Step-by-step explanation:
Given the information from the question:

Next we can use the order of operations to find the value of the expression.

Surface Area (SA) of a Cylinder formula:
SA = 2*pi*r*h+2*pi*r^2
If you fill in the formula:
SA = 2*3.14*2*9+2*3.14*2^2
Simplify:
SA = 6.28*18+6.28*4
SA = 113.04 + 25.12
SA = 138.16 in
I hope I helped
If its wrong I'm super duper extra sorry!
6% tax means 6% of $3.50
Convert 6% to decimal (move decimal 2 spots to the left): 6% ⇒ .06
Multiply 3.50 with .06 = .21 <-- That's .21 cents of 3.50
That means you have to pay an extra 21 cents. Add that to the $3.50 you had to pay.
$3.50 + $0.21 = $3.71 <-- Price after tax
81, if you mean 9 Squared.