using the substitution method. If the answer is a unique solution, present it as an ordered pair (x,y) if not specify wether the answer is "no solution" or "infinitely many solutions"
-4x+y=8
2x+3y=1
2007-02-24 10:36:10 · 4 answers · asked by chickiejam 1 in Science & Mathematics ➔ Mathematics
y=8+4x
substitute into second equation
2x+3(8+4x)=1
2x+24+12x=1
14x+24=1
x=-23/14
y=8+4(-23/14)
y=30/14
(-23/14,30/14)
2007-02-24 10:46:09 · answer #1 · answered by Rob M 4 · 0⤊ 0⤋
rearrange the top equation to solve for y
add 4x to both sides: y=4x+8
now plug this into the second equation and rearrange to solve for x:
2x+3(4x+8)=1
2x+12x+24=1
14x+24=1
14x=-23
x=-23/14
now you can plug this into either equation
-4(-23/14)+y=8
(96/14)+y=8
(48/7)+y=8
y=8-(48/7)
y=8/7
so your ordered pair is (-23/14,8/7)
you should go ahead and divide this to get non-fractional numbers (-1.643,1.143)
and as always, plug your numbers into both equations and check that they work
2007-02-24 10:50:32 · answer #2 · answered by louis504842 2 · 1⤊ 0⤋
-4x+y=8 2x+3y=1
-4x+(-1/3)=8 -2x -2x
+1/3 +1/3 3y=-2x+1
-4x=8 1/3 y=-2/3+1/3
x=-2 1/2 y=-1/3
(-2 1/2,-1/3)
2007-02-24 10:52:54 · answer #3 · answered by maisha 3 · 0⤊ 0⤋
x = -23/14, y = 10/7
Doug
2007-02-24 10:49:38 · answer #4 · answered by doug_donaghue 7 · 0⤊ 0⤋