little stuck here... need steps to see where im messing up
1/2 x + 1/3y=13
2/5x + 1/4y= 10
2007-02-11 05:04:31 · 7 answers · asked by markbernetie 1 in Science & Mathematics ➔ Mathematics
Not correct is not 26
2007-02-11 05:11:10 · update #1
iM VERY confused now....:(
2007-02-11 05:14:25 · update #2
mathassign u r correct...thanks... i wasnt multiplying to get the 780......:)
2007-02-11 05:23:37 · update #3
It's not that hard, you just gotta make the fraction terms have the same denominator
1/2 x + 1/3y=13
2/5x + 1/4y= 10
+____________
becomes
5/10 x + 4/12y=13
4/10x + 3/12y= 10
+____________
9/10x + 7/12y = 26 is your answer
It is the correct answer, but you'll have to multiply those fractions out if you want whole numbers.
2007-02-11 05:10:05 · answer #1 · answered by Roman Soldier 5 · 0⤊ 0⤋
At a guess, I would say the equations are:-
(1/2) x + (1/3) y = 13 -------x by 30
(2/5) x + (1/4) y = 10--------x by - 40
15x + 10y = 390
-16x - 10y = -400---------Add
-x = -10
x = 10
15 x 10 + 10y = 390
150 + 10y = 390
10y = 240
y = 24
Check
1/2 x 10 + 1/3 x 24 = 5 + 8 = 13 as required
2007-02-11 13:27:21 · answer #2 · answered by Como 7 · 0⤊ 0⤋
No, you can't solve this by addition in the beginning....., you must first change both to equivalent equations having no denominators. The lcd for the first equation is 6y, and for the second 20xy. Multiply these out to get equivalent equations and you get:
or you can multiply the to[ one by 1/4, and the bottom by 1/3 to get the y element to drop out after multiplying the top one or the bottom one by a negative 1.... But whether you get rid of the fractions before or later, you still hve to get rid of the fractions.
Ill be back, if no one gives you the answer....
2007-02-11 13:22:39 · answer #3 · answered by April 6 · 0⤊ 0⤋
1/2 x + 1/3y=13
2/5x + 1/4y= 10
Multiply the first by 60
30x+20y = 780
Multiply second by -80
-32x-20y = -800
So now we can add
30x+20y=780
-32x-20y=-800
--------------------
-2x=-20
x = 10
30(10)+20y = 780
300+20y=780
20y = 480
y =24
2007-02-11 13:19:17 · answer #4 · answered by leo 6 · 0⤊ 0⤋
The question is not completed. I will need more info on either x or y to solve these two questions.
2007-02-11 13:19:04 · answer #5 · answered by Professor♫ 2 · 0⤊ 1⤋
What is all of this I'm amaths genius top of my class and I don't understand
2007-02-11 13:07:57 · answer #6 · answered by ladyj 2 · 0⤊ 0⤋
multiply by 6
3x+2y=78
multiply by 20
8x+5y=200
8x+5y=200
3x+2y=78
------------------------
16y+10y=400
-15x-10y=-390
-----------------------
y=10
3x+2y=78
3x+20=78
3x=58
x=58/3
2007-02-11 13:11:20 · answer #7 · answered by iyiogrenci 6 · 0⤊ 0⤋