you are given2 equations which are both true, and you are asked to solve for both x and y. you plan to solve this set of equationsby substituting part of one equation into the other so you end up with an equation that contains only x's or only y's.
2006-08-24 06:24:05 · 3 answers · asked by David G 1 in Science & Mathematics ➔ Mathematics
Take one of the equations and solve for x in terms of y, or vice versa. Then take the new expression and substitute it into the other equation.
For example, suppose you're given
x + 2y = 7
2x + 3y = 2
Take the first equation and solve for x.
x = 7 - 2y
Then take the expression for x and substitute it into the second expression, whic you can now solve for y. Then use the y solution in either of the original equations to solve for x.
2006-08-24 06:27:29 · answer #1 · answered by DavidK93 7 · 0⤊ 0⤋
solve one of the equations for x.
Plug that x into the other equation. Now you have only y :
eg: 3x+4y=10 and x+3y = 7
solving second for x: x=7-3y
then:
3(7-3y)+4y=10 or 21-9y+4y=10 or -5y=-11
now you know y=11/5. Plug in y and solve for x
2006-08-24 13:31:49 · answer #2 · answered by davidosterberg1 6 · 0⤊ 0⤋
just see if this answers your question... consider the following example
2x+4y=9
2x-4y=7
from the above equations
y=1/2, x=4
thats the solution if u are solvin for x and y
2006-08-24 13:31:48 · answer #3 · answered by Anonymous · 0⤊ 1⤋