I need help solving this problem using elimination
2x2y=61
2x+y=7
Please help(Nerd)(Nerd)!!
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I need help solving this problem using elimination
2x2y=61
2x+y=7
Please help(Nerd)(Nerd)!!
2x+2y=61 2x+y=7
2x+2y=61
2y 2y
__________
2x = 61  2y
___________
2 > divide both sides by 2
x = 30.5  y
put this x value into other equation:
2(30.5 y) +y = 7
61  2y + y = 7
y y
______________
61  2y = 7  y
+2y +2y
______________
61 = 7 + y
7 7
______________
56 = y
Now substitute 56 for y:
2x + 2(56) = 61
2x + 112 = 61
2x 61 61 2x
__________________
51 = 2x
________
2 > divide both sides by (2)
x = 25.5
Now put (25.5) for x and 56 for y to check your answers:
2(25.5) + 2(56) = 61
51 + 112 = 61
61 = 61
=]
Elimination means you eliminate either the x term or the y to term to leave you with just y = or x =.
As there are 2 xs in both terms, we can subtract the second term from the first to eliminate the xs.
$\displaystyle 2x  2y = 61$

$\displaystyle 2x + y = 7$
=
$\displaystyle 3y = 68$
$\displaystyle y = 22.666...$
Now that you have y, all you need to do is solve the first equation using y as 68.
So $\displaystyle 2x  2 * 22.6666... = 61$
$\displaystyle 2x = 15.3333...$
$\displaystyle x = 7.6666...$
Very odd answers, but that is correct. The above poster is incorrect as he mistook 2x  2y = 61 to be 2x + 2y = 61.
I realised my mistake. I have edited my post.