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Solving Equations using Elimination help?
I need help with this equation:
Find the point of intersection. Show your work.
3x-2y+2=0
7x-6y+11=0
3 Answers
- 9 years ago
Which would be easiest to eliminate, X or Y? Looks to me that Y would because I can multiply the first equation by 3 and then have two equations with 6y in them. Since they would both have a negative sign I will subtract the second equation from the new first equation:
9x - 6y + 6 = 0
7x - 6y +11 = 0
Subtracting 2nd equation from the first equation gives us 2x - 5 = 0, 2x = 5, x = 2.5
Substitute for 2.5 in for x in second equation (since you have altered the first equation)
7(2.5) -6y+6 = 0, 17.5 - 6y +11 = 0 28.5 = 6y y = 4.75
Now substitute the values for x and y into the original equation to see is everything checks.
3(2.5) - 2(4.75) + 2 = 0, 7.5 - 9.5 + 2 =0 Check!
Source(s): http://www.mathtutoring4free.com/ - PolygonLv 79 years ago
1) 3x-2y+2=0
2) 7x-6y+11=0
Multiply 1) by 3
3) 9x -6y + 6 = 0
Subtract 3) from 2)
4) -2x + 5 = 0
x = 5/2
Substitute in either 1) or 2) to find y
Substituting in 1)
(5/2)*3 - 2y = -2
15/2 - 2y = - 2
15 - 4y = -4
-4y = - 19
y = 19/4
- mrkleen340Lv 59 years ago
3x-2y+2=0
7x-6y+11=0
How might you get rid of y? You could multiply the top equation by -3 to make the coefficient in front of y = +6, so when added together y is eliminated.
(-3)*3x+(-3)*(-2)y+(-3)*2=(-3)*0
-9x+6y-6=0
now add:
7x-6y+11=0
-9x+6y-6=0
---------------
-2x +0y +5 =0
-2x =-5
x = 5/2
Now substitute this back in to either of the original equations:
3(5/2)-2y+2=0
3(5/2)-2y+2=0
15/2 -2y +2 = 0
19/2 -2y =0
-2y = -19/2
y = 19/4
(5/2, 19/4)