math
posted by matt .
A math contest consists of ten problems.Three points are given for each correct answer. One point is deducted for each incorrect answer. Andy answers all the problems and scores 18 points. How many correct answers does he have?

x = number of answers
y = number of incorrect answers
3 x  y = 18
x + y = 10
add the two equations and solve for x
check your answer 
How do you that rbowh? I am really bad at this.(step by step please)

What part of the explanation don't you understand?

How to solve for x.(i am terrible at this)

what did you get when you added the two equations?

That is what I don't get.Please can you show me how to do it.

by the way, x represents number of correct answers  I left that out initially

Step by step is what I meant.

(3x  y) + (x + y) = 18 + 10
4 x = 28
x = ? 
Thank you very kind sir/ma'am you were a big help.

You're welcome Matt.

3*0=0
3*1=3
3*2=6
3*3=9
3*4=12
3*5=15
3*6=18 
3x+y=18
x+y=10
x=4
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