3x-7y=13 and at the bottom will be
6x+5y=7
2007-05-17 17:01:24 · 6 answers · asked by Lucia O 1 in Science & Mathematics ➔ Mathematics
Okay there are different methods of doing this, for ex. elimination, matrix, substitution etc..
I like to use substitution.
3x-7y=13 1st equation
6x+5y=7 2nd equation
What you want to do is solve one of the equations for one of the variables and plug it into the other equation. So let's talk equation 1 and solve for x.
3x - 7y = 13 add 7y to both sides
3x = 7y + 13 divide both sides by 3
x = (7/3)y + 13/3 now plug this into the 2nd equation for x...
6((7/3)y + 13/3) + 5y = 7 okay factor out 1/3 on the left side...
(6/3)(7y + 13) + 5y = 7 which equals
2(7y + 13) + 5y = 7 now distribute the 2 into ( ) and we get...
14y + 26 + 5y = 7 now add like terms...
19y + 26 = 7 now subtract 26 from both sides
19y = -19 divide both sides by 19 to get y by it self...
y = -1 this is your y value now we have to find the x so take this y value and plug it back into the 1st equation for y
3x -7(-1) = 13
3x + 7 = 13 subtract 7 from both sides
3x = 6 divide both sides by 3
x = 2. This is your x.
So the final answer is (2, -1)
If you need further help or clarification email me or im me. Good Luck.
2007-05-17 17:14:50 · answer #1 · answered by Anonymous · 0⤊ 1⤋
3x-7y=13
6x+5y=7
(2)3x-7y=13(2)
6x-14y=26
(-)6x-5y=7(-)
-19y=19
y=-1
plug.
3x-7(-1)=13 -->3x+7=13
is. 3x=6
x=2
Confirmation. 3(2)-7(-1)=13
6+7=13
Im 15 years old, it doesn't matter if I get picked or not. Its just for practice for me as I move on to more advance complicated math. Math is hard, I can tell you that, if you want to get good at it practice, practice, even the best musicians and athletes practiced and got helped along the way. Even the perfect mathematicians get wrong anwsers, its better geting wrong anwsers than correct anwsers. In matter of fact their is no thing as too much practice. Work hard, I can tell you that, its something I want to write to you, I dont care if anyone reads it or not.
With great power comes with great responsablities. Good luck with life, dont let anyone bring you down, I dont know how famous failures did it, but they did it somehow in a possible way. You may be a lucky person to do so.
2007-05-18 00:08:59 · answer #2 · answered by Anonymous · 0⤊ 2⤋
Multiply the first equation by -2, then it becomes...
-6x+14y=-26, then take this add with the second equation...
-6x+14y=-26
+) 6x+ 5y =7
________________
19y=-19 >>>>>>>>>>>> [y=-1]
Take y=-1 plug in to either one of the equations...
6x+5(-1)=7
6x-5=7
6x=12 >>>>>>>>>>>>>>>>>>> [x=2]
2007-05-18 00:08:13 · answer #3 · answered by espms290 4 · 0⤊ 1⤋
3x-7y=13 ---->(1)
6x+5y=7 ---->(2)
2*equ(1)-equ(2) =>
(6x-14y=26)-(6x+5y=7) => -19y=19
=>y=-1
therefore 3x-7(-1)=13
3x+7=13
3x=13-7
3x=6
therefore x=2
therefore x=2,y=-1
2007-05-18 00:11:23 · answer #4 · answered by sriram t 3 · 0⤊ 1⤋
15x - 35y = 65
42x + 35y = 49-----ADD
57 x = 114
x = 2
12 + 5y = 7
5y = - 5
y = - 1
Solution is x = 2 , y = - 1
2007-05-18 08:42:53 · answer #5 · answered by Como 7 · 0⤊ 0⤋
x = -6
y = -1
2007-05-18 00:11:48 · answer #6 · answered by wondermarvel_charmchith 2 · 0⤊ 1⤋