6. x = y + 7
y = 8 + 2x
(1 point)
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7. 3x + 4y = 12
y = -2x + 10
(1 point)
8. 4x + 9y = 24
y = -x + 2
2007-12-14 03:58:29 · 6 answers · asked by Sexy_Love 1 in Science & Mathematics ➔ Mathematics
6. x = y + 7
y = 8 + 2x
y = x – 7 = 8 +2 x
x = – 15
y = – 22
7. 3x + 4y = 12
y = – 2x + 10
3x + 4( – 2 x) = 12
3 x – 8 x = 12
– 5 x = 12
x = – 12/5 = – 2.4
y = 4.8 + 10
= 14.8
8. 4x + 9y = 24
y = – x + 2
4x + 9y = 24
4x + 9 ( – x + 2) = 24
4 x – 9 x + 18 = 24
– 5 x = 6
x = – 6/5 = 1.2
y = – 1.2 + 2 = 0.8
2007-12-14 04:16:26 · answer #1 · answered by Pranil 7 · 0⤊ 0⤋
6. x = y + 7
y = 8 + 2x
x-7 = 8+2x --> -3x= 15 --> x = -5, so y = -2
7. 3x + 4y = 12
y = -2x + 10 --> 4y = -8x +40
3x -8x +40 = 12
-5x = -28
x = 28/5, so y = -56/5+2 = -66/5
8. 4x + 9y = 24
y = -x + 2 --> 9y = -9x +18
4x -9x +18 = 24
-5x = 6
x = -6/5, so y = 6/5 +2 = 3 1/5
2007-12-14 12:14:53 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
7): 3x + 4y = 12
y = -2x + 10
just use the 2nd equation put it into the first; wherever you see a "y" in the first equation, just plug in (-2x + 10)
3x + 4(-2x+10) = 12
3x - 8x + 40 = 12
-5x = -28
x = 28/5
now use this value of x to find y in the 2nd equation
y = -2 (28/5) + 10
y = -56/5 + 50/5
y = -6/5
you can do 8) the same way
4x + 9(-x+2) = 24
4x -9x + 18 = 24
-5x = 6
x = 6/5
y = -(6/5) + 2
y = -6/5 + 10/5
y = 4/5
hope this helps
2007-12-14 12:03:03 · answer #3 · answered by shadowsjc 2 · 0⤊ 0⤋
6) x = y + 7
y = 8 + 2x
substitute the value of y in 2nd equation to the 1st equation
x=8+2x+7
x-2x=8+7
-x=15
x=-15
substitute this value of x in equation 2 to get the vaue of y
y=-2x+10
y=-2*{-15}+10
y=30+10
y=40
7.) 3x + 4y = 12
y = -2x + 10
substitute the value of y in 2nd equation to the 1st equation
3x+4(-2x+10)=12
3x-8x+40=12
3x-8x=12-40
-5x=-28
5x=28
x=28/5 or 5.6
substitute this value of x in equation 2 to get the vaue of y
y=-2x+10
y=-2*{5.6}+10
y=-11.2+10
y=-1.2
8. 4x + 9y = 24
y = -x + 2
substitute the value of y in 2nd equation to the 1st equation
4x+9(-x+2)=24
4x-9x+18=24
4x-9x=24-18
-5x=6
5x=-6
x=-6/5
substitute this value of x in equation 2 to get the vaue of y
y=-x+2
y=-{-6/5}+2
y=6/5+2
LCM 5
5y=6+10
5y=16
y=16/5
2007-12-14 12:08:10 · answer #4 · answered by Siva 5 · 0⤊ 0⤋
In real life I come across this question several times a day.
2007-12-14 12:11:27 · answer #5 · answered by Anonymous · 0⤊ 0⤋
1)
(-15,-22)
2)
(5.6,-1.2)
3)
(-1.2,3.2)
2007-12-14 12:03:59 · answer #6 · answered by shree 1 · 0⤊ 0⤋