Solve the system by addition.
–5x + 2y = 10
x – 3y = 11
2006-09-10 11:07:58 · 12 answers · asked by pjaxdriver13 1 in Science & Mathematics ➔ Mathematics
Miltiply the second equation by 5
5x-15y=55
Now add them.
2006-09-10 11:10:07 · answer #1 · answered by Barkley Hound 7 · 1⤊ 0⤋
–5x + 2y = 10
x – 3y = 11
similar to
–5x + 2y = 10
5(x – 3y) = 11*5
similar to
–5x + 2y = 10
5x – 15y= 55
we add both system members we have : 0x -13y =65
y=-65/13 = -5
to get x let's subsitute the y valu in any equation above, let's take
x-3y=11 the x +15=11 then x=-4
so here's it x=-4 and y=-5
2006-09-10 18:26:34 · answer #2 · answered by Gaztastic 2 · 0⤊ 0⤋
You're supposed to add the two systems like this:
-5x + 2y=10
x - 3y= 11
-4x - y= 21
Hope it helps. There's really not much I can do, since I'm writing this on the computer...
2006-09-10 18:12:42 · answer #3 · answered by Barb 3 · 0⤊ 1⤋
It depends on how rigorous (sticky) you and your math teacher are.
To solve for BOTH variables by addition:
Solving for y is the easiest to see.
multiply the 2nd equation by 5, then add:
'-5x + 2y = 10
+5x -15y = 55
Solving for x BY ADDITION takes a little more work:
Multiply each equation by the absolute value of the coefficient of y in the other. then add:
-15x + 6y = 30
''10x -' 6y = 22
( I use ' to adjust spacing so that I can align columns. It has no bearing on the math.)
2006-09-10 18:28:02 · answer #4 · answered by Helmut 7 · 0⤊ 0⤋
Ha i love this
-5x+2y=10 (x3)
x-3y=11 (x2)
1. -15x+6y=30
2. 2x-6y=22 add equation 1. and equation 2.
3. -13x= 52 simplify for x by dividing both sides by -13
x= -4
substitute -4 for x in equation 2.
2(-4)-6y=22
-8-6y=22
-6y=22+8
-6y=30 divide both sides by -6 to solve for y
y=-5
2006-09-10 18:19:49 · answer #5 · answered by ? 1 · 0⤊ 0⤋
-5 (11+3y) +2y = 10
-55 -15y+2y = 10
-13y = 65
y = -65/13
y=-5
x-3(-5) = 11
x+15 = 11
x = -4
check:
-4 -3(-5) = 11
-4+15 = 11 (good)
-5(-4) + 2(-5) = 10
20-10 = 10 (good)
2006-09-10 18:12:41 · answer #6 · answered by Anonymous · 1⤊ 0⤋
if you multiply the second equation by five, then it will be
-5x + 2y = 10
5x - 15y = 55
then add. the x's cancel out, and you can solve for y. then subsitute the y into the equation to find x.
2006-09-10 18:31:22 · answer #7 · answered by maroon_passport 1 · 0⤊ 0⤋
lol, i wont solve it for you tho.
Pick to solve x or y. Say we're solving X, multiply both sides of both equations by 5 to cancel out X, then solve for Y. Substitute the Y into any 1 equation and VOILA, you got the answer
2006-09-10 18:11:32 · answer #8 · answered by littolonerboi 2 · 0⤊ 0⤋
first 5xfirst equation to give
5x-15y=55
then add the two equations
-13y=65
so y=-5
substituting into the second equation gives
x+15=11
so x=-4
2006-09-10 18:15:05 · answer #9 · answered by firstlennsman 1 · 1⤊ 0⤋
x – 3y = -24
2006-09-10 18:12:44 · answer #10 · answered by Anonymous · 0⤊ 1⤋