I could use some help using the subitution method to solve this problem.
4x+5y+-1=-12+2x
x-3y+2=-3-x
2007-11-22 03:45:26 · 8 answers · asked by Adventurebound75 1 in Science & Mathematics ➔ Mathematics
2x + 5y = - 11
- 2x + 3y = 5--------ADD
8y = - 6
y = - 3 / 4
2x - 15/4 = - 11
2x = - 44 / 4 + 15/4
2x = - 29 / 4
x = - 29 / 8
x = - 29 / 8 , y = - 3 / 4
x = - 29/8 , y = - 3/4
2007-11-26 03:28:42 · answer #1 · answered by Como 7 · 0⤊ 0⤋
simplify the 1st equation and isolate a variable:
4x+5y+-1=-12+2x
2x + 5y = -11
x = -5y - 11
x = -5/2y - 11/2
simplify the next equation
x-3y+2=-3-x
2x - 3y = -5
substitute:
2 (-5/2y - 11/2) - 3y = -5
-5y - 11 - 3y = -5
-8y = 6
y = - 6/8 = - 3/4
plug this back into the 1st equation:
x = -5/2(-3/4) - 11/2
x = 15/8 - 11/2
x = 15/8 - 44/8
x = - 29/8
2007-11-22 03:55:30 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Okay, so you solve either equation for 1 variable:
I picked the bottom one and I solved for y:
x-3y+2 = -3-x (Add 2 to both sides)
x-3y=-1-x (Subtract x from both sides)
-3y = -1-2x (Divide both sides by -3)
y = (-1-2x)/-3 OR (1+2x)/3
Then, plug this into the top equation to get your x:
You end up with an x value of -19/8. Just follow the same steps as the first substitution but be careful of the fraction in the 2nd equation.
2007-11-22 03:55:57 · answer #3 · answered by rcds23 6 · 0⤊ 0⤋
First, simplify the second equation:
x - 3y + 2 = -3 - x
2x - 3y = -5
x = (3/2)y - 5/2
Then, substitute the result for x into the first equation:
4[(3/2)y - 5/2] + 5y + (-1) = -12 + 2x
The rest is just algebraic simplification.
2007-11-22 03:52:06 · answer #4 · answered by Scott H 6 · 1⤊ 0⤋
#1 : 4x + 5y - 1 = -12 + 2x
2x = -5y - 11
#2 : x - 3y + 2 = -3 - x
2x = 3y - 5
sustitution of 2x (#2) to 2x (#1), or vice versa, gives
3y - 5 = -5y - 11
8y = -6
y = - (3/4)
2x = 3y - 5
2x = 3 (- (3/4)) - 5
2x = - (29/4)
x = - (29/8)
2007-11-22 03:54:14 · answer #5 · answered by Lucky 4 · 1⤊ 0⤋
4x +5y + -1=-12+2x
4x-2x+5y=-12+1
2x +5y =-11
x-3y+2=-3-x
x+x -3y = -3-2
2x -3y = -5
2007-11-22 05:20:39 · answer #6 · answered by mb_can 2 · 0⤊ 0⤋
4x+5y+-1=-12+2x
x-3y+2=-3-x
the second equation:
x-3y+2=-3-x
-3y+2=-3-2x
-3y=-5-2x
2x-3y=-5
2x=-5+3y then put this back into the 1st equation to get y...
4x+5y+-1=-12+2x
2(-5+3y)+5y-1=-12-5+3y
-10+6y+5y-1=-12-5+3y combine like terms
11y-11=3y-17
8y-11=-17
8y=-6
y=-3/4(or -.75)
now find x.....
x-3y+2=-3-x
x-3(-3/4)+2=-3-x
x+2.25+2=-3-x
x+4.25=-3-x
2x+4.25=-3
2x=-7.25
x=-3.625(or -29/8)
2007-11-22 03:58:41 · answer #7 · answered by sweEtiE_pi 2 · 0⤊ 0⤋
2x+5y=-11
2x=3y-5
(3y-5)+5y=-11
8y = -6
y = -3/4
2x+5(-3/4) = -11
2x = -11 +15/4= -39/4
x = -29/8
2007-11-22 03:55:23 · answer #8 · answered by norman 7 · 0⤊ 0⤋