Simplify-
2/5x - 1/3y = 1
3/5x + 2/3 = 5
2007-08-19 07:16:28 · 10 answers · asked by niki 2 in Science & Mathematics ➔ Mathematics
where did u get the 15?
2007-08-19 07:21:22 · update #1
You missed out the y in the second equation.
1) Multiply by 15 to get rid of the fractions.
6x - 5y = 15...(1)
9x +10y = 75..(2)
2) Multiply (1) by 2 to get the ys the same.
12x - 10y= 30
9x +10y = 75
...................... 3)Add to eliminate the y.
21x = 105
x = 5.
4) Substitute for x in 2)
9(5) = 10y = 75
45 + 10y = 75
10y = 75-45
10y = 30
y = 3
So x=5 and y = 3.
(Really you should have written the equations 2x/5 - 1y/3 = 1 and 3x/5 + 2y/3 = 5. The way you wrote it makes it appear it's
2 over 5x - 1 over 3y equals 1 etc.)
2007-08-19 07:25:18 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Did you miss a 'y' in 3/5x + 2/3 = 5?
2/5x - 1/3y = 1......(1)
3/5x + 2/3y = 5......(2)
2*(1)+(2): 7/5x = 7 => x = 5, y = 3
---------
Ideas: Since the y coefficient in (2) is twice the negative y coefficient in (1), 2*(1)+(2) can get rid of y.
2007-08-19 14:21:31 · answer #2 · answered by sahsjing 7 · 0⤊ 0⤋
2/5x - 1/3y = 1
3/5x + 2/3 = 5
3/5x = 5 - 2/3 =13/3
5x/3 = 3/13
x = 3/13^3/5 = 9/65.
2/5x - 1/3y =1
2/5^65/9 - 1/3y = 1
1/3y = 130/45 - 1
1/3y = 17/9
3y = 9/17
y = 3/17
2007-08-20 11:04:32 · answer #3 · answered by vr n 2 · 0⤊ 0⤋
3/5x + 2/3 = 5
3/5x = 5 - 2/3
3/5x = 4 1/3
3/5x = 13/3
x = (13/3)(5/3)
x = 65/9
2/5x - 1/3y = 1
(2/5)(65/9) - 1/3y = 1
26/9 - 1/3y = 1
26/9 - 1 = 1/3y
17/9 = 1/3y
y = (17/9)(3/1)
y = 17/3
y = 5 2/3
2007-08-19 21:42:30 · answer #4 · answered by Kemmy 6 · 0⤊ 0⤋
I assumed you miss a 'y' in the equation 3/5x + 2/3 = 5
Then
2/5x - 1/3y = 1
3/5x + 2/3y = 5
Multiply each equation by 15:
6x - 5y = 15
9x + 10y = 75
Multiply 1st equation by 2:
12x - 10y = 30
9x + 10y = 75
------------------------
21 x = 105 (addition method)
x = 105 / 21
x = 5
Replace the value of x in the equation 9x + 10y = 75 to solve y:
9*5 + 10y = 75
10y = 75 - 45
10y = 30
y = 30/10
y = 3
-------------------
Solution:
x = 5
y = 3
-------------------
2007-08-19 14:28:41 · answer #5 · answered by Anonymous · 0⤊ 0⤋
2/5x - 1/3y = 1
3/5x + 2/3 = 5
3/5x + 2/3 = 5
3/5x = 5 - 2/3
3/5x = 15/3 - 2/3
3/5x = 13/3
9x = 65
x = 65/9
2/5x - 1/3y = 1
2/5(65/9) - 1/3y = 1
26/9 - 1/3y =1
-1/3y = 1 - 26/9
-1/3y = 9/9 - 26/9
-1/3y = -17/9
y = -17/9 * -3
y = 17/3
(65/9,17/3)
2007-08-19 14:31:13 · answer #6 · answered by fofo m 3 · 0⤊ 1⤋
2/5x - 1/3y = 1 <-- Eq1
3/5x + 2/3 = 5 <-- Eq 2
4/5x -2/3y =2 <-- 2*Eq 1
7/5 x = 7 <-- Eq 2+2*Eq 1
x = 5
2/5 * 5 - 1/3 y =1
-1/3y = -1
y = 3
2007-08-19 14:25:38 · answer #7 · answered by ironduke8159 7 · 0⤊ 0⤋
I'm a little rusty, but don't you cross out the equal values in the fraction - the two 5's and the two 3's therefore 2x - 1y = 1 and 3x + 2(y?) = 5 ???
So logically 2 - 1 = 1 and 3 + 2 = 5 (?)
2007-08-19 14:22:37 · answer #8 · answered by Connie Lindquist's!® 2 · 0⤊ 2⤋
multiply everything by 15
6x - 5y = 15
9x + 10y = 75
35y = 105 so y = 21/7 = 3
so x = 5
2007-08-19 14:19:33 · answer #9 · answered by Anonymous · 1⤊ 1⤋
x=13/5
y= 3/25
2007-08-19 14:22:01 · answer #10 · answered by prem l 1 · 0⤊ 2⤋