|
Question 282533: solve the equations by multiplying by a factor :
2x+y=5
3x-3y=3
Answer by Monkibat(7)   (Show Source):
You can put this solution on YOUR website! solve the equations by multiplying by a factor :
2x+y=5
3x-3y=3
When looking at this problem look for what equation is easiest to multiply a number by and will result in the x or the y to cancel out with the other equation. In this particular problem, look at the y's in both equations. One y is positive and one y is negative. If the positive y was a 3y it would cancel out with the -3y.
In that case multiply the whole top equation 2x+y=5 by 3. The new equation will be 6x+3y=15. Now add the new equation 6x+3y=15 to 3x-xy=3. 6x+3x=9x, 3y-3y cancel out, and 15+3=18. Now you have 9x=18. Divide both sides by 9 to solve for x. x=2
Now take the 2 and plug it in for x in one of the original equations to solve for y. We will plug it into 2x+y=5, 2(2)+y=5, 4+y=5. Now subtract 4 from both sides. y=1.
Now you have to check your answers by plugging in 2 for x and 1 for y into one of the original equations. We will plug it into 3x-3y=3, 3(2)-3(1)=3, 6-3=3. That is correct, 6 minus 3 equals three. Your answer is correct. x=2 and y=1
|
|
|
| |
