Another Question: Solving Systems in Linear Equations?

Question

x + 2y = 7
2x - y =4

I came up with 4. Is this correct? I'm using the substitution method.

I came up with 2. Is this right?

Answer 1

the answer must come same weather you use substitution or equating coefficients method. in this particular case equating coefficient method is easier to apply. though i am giving you both methods.
1) equating coefficient method.
X + 2Y =7.........1X 1(multiplying equation 1 by 1 and equation 2 by 2
2X - Y = 4 ..........2X 2.
X+2Y =7
4X- 2Y= 8
.....................
5X = 15
X=15/5
X=3
putting this value of X in equation 1,
3+2Y=7
2Y=7-3
2Y=4
Y=4/2=2
substitution method:-----
by equation 1, X= 7-2Y, putting this value of X in equation 2
2(7-2Y)-Y=4
14-4Y-Y=4
-5Y=4-14
-5Y= -10
Y= -10/-5
Y=2, now putting this value of Y in X=7-2Y
X=7-2(2)
X=7-4
X=3
therefore by either methods X=3, Y= 2 are solution of given linear equations in two variables.
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Answer 2

so for the first one, both equations are equivalent to y so set the equations equivalent to at least one yet another like this 2x + a million = 3x - 7 once you remedy this, you get x = 8 for the second one one, you ought to get y by employing itself for both equations x - y = 4 will change into x - 4 = y -6x - 2y.... this isn't an equation. regardless of the indisputable fact that, you ought to easily get y by employing itself and then set the equations equivalent to at least one yet another. searching the x and y coordinates is so ordinary as choosing an x coordinate and fixing for y. %. any cost for x and then the cost of y must be the y cooridinate.

Answer 3

x=7-2y
x=2+(y/2)

7-2y=2+(y/2)
solve this and you will get:
y=2
and x=3


YAP Its right if its y=2 and x=3

Answer 4

Shoot! I should know this, but my brain just isn't clicking. I took Algebra I last year and passed it, barely! I'm so sorry, I can't remember what my teacher taught me; she was a weird teacher anyway; she smiled to much...and still smiled when she was mad...I think you're right though...