Solve by substitution.
3x+y=-8
-2x-y=6
MATH HOMEWORK! PLEASE HELP?
2014-02-15 12:29 am
回答 (7)
2014-02-15 9:02 pm
✔ 最佳答案
add the equationsx = -2
and so y = -2 too
2014-02-15 9:05 am
3x+y=-8 or y = -3x - 8
-2x-y=6
substitute first equation into second equation:
-2x - (-3x - 8) = 6
-2x + 3x + 8 = 6
x = -2
using first equation:
y = -3(-2) - 8 = -2
check using second equation:
-2(-2) - (-2) = 6 checks
x = -2, y = -2
- .--
-2x-y=6
substitute first equation into second equation:
-2x - (-3x - 8) = 6
-2x + 3x + 8 = 6
x = -2
using first equation:
y = -3(-2) - 8 = -2
check using second equation:
-2(-2) - (-2) = 6 checks
x = -2, y = -2
- .--
2014-02-15 8:40 am
3x+y=-8
-2x-y=6
,,,,,,,,,,,,,,,,,,
-y= 2x+6
y= -2x-6
Substitute this value for y into equation 1 to find x
3x+y=-8
3x -2x-6=-8
x = 8+6
x= 14
,,,,,,,,,,,,,,,,,
Substitute this value for x into equation 2 to find y
-2x-y=6
-2(14) -y=6
-28 -y=6
-y= 28+6
-y= 34
y= -34
( 14,-34)
-2x-y=6
,,,,,,,,,,,,,,,,,,
-y= 2x+6
y= -2x-6
Substitute this value for y into equation 1 to find x
3x+y=-8
3x -2x-6=-8
x = 8+6
x= 14
,,,,,,,,,,,,,,,,,
Substitute this value for x into equation 2 to find y
-2x-y=6
-2(14) -y=6
-28 -y=6
-y= 28+6
-y= 34
y= -34
( 14,-34)
2014-02-15 8:36 am
isolate y in one of the equations so say in the first one: y= -3x-8 and then sub that into the second one where y is and solve for x and once you get x, sub the x into the first equation and solve for y :)
2014-02-15 8:36 am
-2x-y =6
-2x-6= y
sub into formula 1
3x + (-2x-6) = -8
3x -2x-6 = -8
x=-8+6
x= -2
Solve for y
y= -2x - 6
y= -2(-2) - 6
y = 4 -6
y = -2
-2x-6= y
sub into formula 1
3x + (-2x-6) = -8
3x -2x-6 = -8
x=-8+6
x= -2
Solve for y
y= -2x - 6
y= -2(-2) - 6
y = 4 -6
y = -2
2014-02-15 8:31 am
(-2,-2)
2014-02-15 8:39 am
Make -2x-y=6 move to just y=-2x+6 then plug that into the first equation 3x+(-2x+6)=-8 then solve for the variables
收錄日期: 2021-05-01 15:08:37
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