2006-12-02 07:26:09 · 7 answers · asked by brandy 1 in Education & Reference ➔ Homework Help
5x+2y=3 ..........1)
x-4y=17 ............2)
multiply equation 1)by2 to make coefficients of y equal then solving.
10x+4y=6
x-4y=17
......................
11x=23
x=23/11
x-4y=17
23/11-4y=17
-4y=17-23/11
-4y= (187-23)/11
-4y=164/11
y= -41/11
2006-12-02 07:34:59 · answer #1 · answered by flori 4 · 0⤊ 0⤋
well, you have to divide the equation into two like this:
5x + 2y = 17
3x - 4y = 17
and you have to have one of the unknown factors (x or y) with the sa me number in front of them only with different signs. you can do this by multiplying the first equation by 2 so:
5x + 2y = 17 * 2
3x - 4y = 17
=>
10x + 4y = 34
3x - 4y = 17
after this you add the two equations and you get
10x + 4y = 34
+
3x - 4y = 17
=
13x = 51 => x=51/13
you do the same thing with y by multiplying the first equation by 3 and the second by (-5)
5x + 2y = 17 * 3
3x - 4y = 17 * (-5)
and you get
15x + 6y = 51
-15x + 20y = -85
by adding the two equations you get
15x + 6y = 51
+
-15x + 20y = -85
=
26y = -34 => y= -34/26 => y= -17/13
final answer
x = 51/13
y = -17/13
2006-12-02 16:16:55 · answer #2 · answered by bubicoo 2 · 0⤊ 0⤋
5x + 2y =3......(1)
x-4y=17..........(2)
(2)x5
5x-20y=85.......(3)
(3)-(1) gives -22y=82.... and solve the rest
"Thanks Scabius Fretful ...I'm very careless as usual but i don't think there's a typo?"
ANOTHER METHOD is to make x the subject(easier this way) in eqn (2) (ie x=17+4y) and sub into eqn(1)
2006-12-02 15:38:12 · answer #3 · answered by Ken T 1 · 0⤊ 0⤋
I would use the subsitution method or elimenation method however you like. I'll show you the elimenation method:
Example problem: 3x + 5y = 16, x - 10y = 23
First take the problem 3x + 5y =16
You need to elimate one of the variables do this multipling the equation by 2 in order to have one like term with the other equation.
you now have 6x + 10y =32
x - 10y=23
You can now use the elimation method to make it instead
6x + 10y =32
+ x - 10y =23
7x=55
55/7=7.85 x=7.85
Now solve for y
2006-12-02 15:48:37 · answer #4 · answered by Fastdog 2 · 0⤊ 0⤋
5x+2y=3x-4y=17
First you have to bring all numbers and letter to one side of the equation. Thatws all i know. sorry, i was never good at algebra. I hated it. But thats the only part i can remember.
2006-12-02 15:36:13 · answer #5 · answered by Tasha 3 · 0⤊ 0⤋
I somehow think you mis-typed something. E-mail me with the correct equation, and I'll supply the answer.
Sorry Ken T, you slipped.
(3) - (1) gives - 22y = 82.
2006-12-02 15:41:35 · answer #6 · answered by Scabius Fretful 5 · 0⤊ 0⤋
are u sure you typed it in right?
2006-12-02 15:33:07 · answer #7 · answered by Anonymous · 0⤊ 0⤋