Solve the system using substitution:
x - 2y = -1
y = -x - 7
2006-06-30 01:22:55 · 10 answers · asked by Mathe Geek 1 in Science & Mathematics ➔ Mathematics
x-(-2 -7)=-1
x+2x+14=-1
3x=-15
x = -5
y=-x-7
y=-(-5) - 7
y=5-7
y = -2
2006-06-30 01:30:44 · answer #1 · answered by someguy 3 · 0⤊ 0⤋
x - 2y = -1
y = -x - 7
x - 2(-x - 7) = -1
x + 2x + 14 = -1
3x + 14 = -1
3x = -15
x = -5
y = -5 - 7
y = -12
(-5,-12)
2006-06-30 12:08:18 · answer #2 · answered by Sherman81 6 · 0⤊ 0⤋
x - 2y = -1
x = 2y -1 --> now substitute
x = 2 (-x - 7) -1
x = -2x -14 -1
x = -2x -15
3x = -15
x = -5 --> now insert to find y
x -2y = -1
-5 -2y = -1
-2y = -1 +5
-2y = 4 -->divide by the coefficient -2
y = -2
answer for system (-5,-2)
2006-06-30 01:58:44 · answer #3 · answered by klund_pa 3 · 0⤊ 0⤋
x - 2y = -1
y = -x - 7
then:
x = 2y - 1
y = - (2y - 1) - 7
y = -2y + 1 - 7
y = -2y -6
3y = -6
y = -2
then:
y = -x - 7
-2 = -x - 7
2 = x + 7
x = -5
y = -2
x = -5
2006-06-30 01:33:25 · answer #4 · answered by jasonalwaysready 4 · 0⤊ 0⤋
no longer difficult: 3x + 4y = -sixteen, 3x + 11 = y... or; 3x - y = -11 Subtract out the 2nd equation from the 1st. 5y = -5 y = -a million And now remedy for x: 3x + 4y = -sixteen, 3x + 11 = y 3x + (-4) = -sixteen, 3x + 11 = (-a million) 3x = -12, 3x = -12 x = -4, x = -4 y = -a million and x = -4 No mistaking it from the above. this is an ironclad info!
2016-10-31 23:35:28 · answer #5 · answered by ? 4 · 0⤊ 0⤋
solve for x in the first equation
x-2y=-1
x= 2y -1
then substitute in the second equation
y= - (2y -1) -7
y= -2y +1 -7
y= -2y -6
3y=-6
y=-2
then substitute in original equation
x= 2y -1
x=2 (-2) -1
x= -4-1
x= -5
therefore, (-5, -2)
2006-06-30 03:45:29 · answer #6 · answered by mike 2 · 0⤊ 0⤋
x - 2(-x-7) = -1
x + 2x + 14 = -1
3x = -15
x = -5
y = -(-5) - 7
y = 5 - 7
y = -2
2006-06-30 01:29:33 · answer #7 · answered by cas 3 · 0⤊ 0⤋
x - 2(-x-7) = -1
x + 2x +14 = -1
3x = -15
x = -5
y = -(-5) -7
y = -2
P(-5,-2)
2006-06-30 01:38:01 · answer #8 · answered by Bruce S 1 · 0⤊ 0⤋
x-2(-x-7)=-1
x+2x+14=-1
3x+14=-1
3x=-15
3x/3=-15/3
x=-5
2006-06-30 06:36:46 · answer #9 · answered by Tracy J 1 · 0⤊ 0⤋
x = - 5
y = -2
2006-06-30 01:33:01 · answer #10 · answered by rickyh606 2 · 0⤊ 0⤋