x + y = 20
30x + 25y = 550
2007-10-13 03:04:39 · 6 answers · asked by geomon2gyromon 1 in Science & Mathematics ➔ Mathematics
x+y=20.....(1)
30x+25y=550...(2)
From (1)
we get
x=20-y
substituting x by 20-y in equn 2
30(20-y)+25y=550
600-30y+25y=550
-5y=550-600= -50
y= -50/-5=10
plugging y in x=20-y
x=20-10=10
Therefore x=y=10
[01]
2007-10-13 03:21:15 · answer #1 · answered by alpha 7 · 0⤊ 1⤋
x + y = 20
30x + 25y = 550
x=20-y
30(20-y) + 25y=550
600 -30y + 25y=550
600 – 5y=550
-5y=550-600
-5y=-50
y=50/5
y=10
30x +25(10)=550
30x +250=550
30x=550-250
30x=300
x=300/30
x=10
2007-10-13 10:35:05 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The person above me,Jeff,his answer is wrong.
let x+y=20 be equation 1.
30x+25y=550 be equation 2.
from equation 1, x=20-y
sub it into equation 2,
30(20-y) + 25y=550
600-30y+25y=550
600-5y=550
-5y=-50
y=10
sub y=10 into equation 1,you will get
x=10.
x and y are both 10.
2007-10-13 10:20:52 · answer #3 · answered by dark 3 · 1⤊ 0⤋
x+y=20
-y -y
x= -y+20
30x+25y=550
30(-y+20)+25y=550
-30y+60+25y=550
-5y+60=550
-60 -60
-5y=490
y= -98
2007-10-13 10:15:10 · answer #4 · answered by jeff 2 · 0⤊ 2⤋
x=20-y
30(20-y)+25y=550
600-30y+25y=550
600-5y=550
-5y=-50
-5y/-5=-50/-5
y=10
x+y=20
x+10=20
x=10
2007-10-13 11:33:07 · answer #5 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
x+y=20
y=-x+20
30x+25(-x+20)=550
30x+-25x+500=550
5x+500=550
5x=50
x=10
10+y = 20
y=10
Answer: (10,10)
2007-10-13 10:43:41 · answer #6 · answered by Anonymous · 0⤊ 0⤋