3x-2y=7
4x-3y=1
i need to find both x and y
i got weird numbers like x=31 and y= 23.5 so i think i'm wrong helpp pleasee
2006-09-01 04:32:05 · 10 answers · asked by islAnd_paradisex4 1 in Science & Mathematics ➔ Mathematics
3x-2y=7.........(i)
4x-3y=1.........(ii)
(i)*4.........12x-8y=28
(ii)*3.........12x-9y=3
After minusing these two equations we get, y=25
Then, put the value of y in a equation to find the value of x.
4x-3y=1
or, 4x-3*25=1
or, 4x-75=1
or, 4x=76
or, x=19
2006-09-01 04:47:01 · answer #1 · answered by Anonymous · 0⤊ 0⤋
3x - 2y = 7
4x - 3y = 1
- - - - - - - - - - - - - - - -
Elimination of x
Multiply the top equation by 4 and the bottom equation by -3
4(3x) - 4(2y) = 4(7)
-3(4x) -3(-3y) = -3(1)
12x - 8y = 28
-12 +9y = -3
- - - - - - - - - - - - -
y = 25
Insert the y value into the top equation
- - - - - - - - - - - - - - - - - - - - - - - - - - -
Solving for x
3x - 2y = 7
3x - 2(25) = 7
3x - 50 = 7
+ 50 + 50
Adding + 50 to both sides
3x = 57
3x/3 = 57/3
Dividing 3 from both sides of the equation
x = 19
Insert the value into the equations
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Solving the top equation
3x - 2y = 7
3(19) - 2(25) = 7
57 - 50 = 7
7 = 7
- - - - - - - - - - - - - - - - - - - - - - - - - - -
Solving the bottom equation
4x - 3y = 1
4(19) - 3(25) = 1
76 - 75 = 1
1 = 1
- - - - - - - - - - - - - - - - - - -
The answer is:
x = 19
y = 25
2006-09-01 13:07:11 · answer #2 · answered by SAMUEL D 7 · 0⤊ 0⤋
To solve this type of problem you have to either get the x or y coefficients the same. Then you cansubtract one equation from the other. In the example the x had 3 and 4 so you could multiply the first by 4 and the second by 3 then both would have 12. Or since y had 2 and 3 you could multiply the first by 3 and the second by 2 then both would have 6.
2006-09-01 11:42:33 · answer #3 · answered by Barkley Hound 7 · 0⤊ 0⤋
multiply top eq. by 4 .... bottom by 3 ....yields
12x - 8y = 28
12x - 9y = 3 subtract two from one...
0x + y = 25... ( y = 25 is solution)...substitute 25 for y in eq1.....
3x - 2(25) = 7
3x - 50 = 7
3x = (7 + 50) = 57
x = 57 / 3 = 19
check : eq2- 4(19) - 3(25) = 1
76 - 75 = 1 check
2006-09-01 11:42:32 · answer #4 · answered by Brian D 5 · 0⤊ 0⤋
3x-2y=7, so 9x-6y=21 (multiplying both sides by 3).
4x-3y=1, so 8x-6y=2 (multiplying both sides by 2).
If 9x-6y =21, then 6y=9x-21.
If 8x-6y=2, then 6y=8x-2.
So, 9x-21=8x-2. Subtract 8x from each side to get:
x-21=-2, so:
x=19.
Plug x=19 into the fist equation to get 3*(19) - 2y=7, so:
57-2y=7, so
2y=50, so:
y=25.
2006-09-01 11:43:52 · answer #5 · answered by ns220 3 · 0⤊ 0⤋
x = 19
y = 25
2006-09-01 11:47:57 · answer #6 · answered by agarwalsankalp 2 · 0⤊ 0⤋
x = 19
y = 25
2006-09-01 11:36:56 · answer #7 · answered by Anonymous · 0⤊ 0⤋
x=19 and y=25
Multiply 1st eqn by 3 and 2nd by 2
Subtract 2 from 1 U get the value of x put in any eqn and get y
2006-09-01 11:35:41 · answer #8 · answered by amandeep s 3 · 0⤊ 0⤋
x=19
y=25
2006-09-01 11:44:44 · answer #9 · answered by credo quia est absurdum 7 · 0⤊ 0⤋
x=19
y=25
If you check you get
(First equation)
3x-2y=7
57-50=7
(second equation)
4x-3y=1
76-75=1
Ope that helps you
2006-09-01 12:10:10 · answer #10 · answered by juicy 1 · 0⤊ 0⤋