Find the values of x and y that solve the following system of equations:
-7x-6y=17
4x+5y=-5
2007-05-29 18:41:18 · 11 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
y= 3, x= -5
4*(-7x-6y)+7(4x+5y)=4*17+7*-5 yields y=3, thus giving x = -5
2007-05-29 18:50:12 · answer #1 · answered by heathenboilermaker 1 · 0⤊ 0⤋
1) -7x - 6y = 17
2) 4x + 5y = -5
Multiply each equation by a different constant so that when you add the equations together one of the variables is eliminated. For example, Multiply equation 1 by 5 and equation 2 by 6
1a) -35x - 30y = 85
2a). 24x + 30y = - 30
. . .- - - - - - - - - - - - -
. . . - 11x . . . . .= 55
x = - 5
Plug into equation 1
-7(-5) - 6y = 17
35 - 6y = 17
- 6y = - 18
y = 3
Check in equation 2
4(-5) + 5(3) = - 5
- 20 + 15 = - 5
- 5 = - 5
x = -5, y = 3 is the point of intersection
2007-05-30 01:52:54 · answer #2 · answered by kindricko 7 · 0⤊ 0⤋
-7x - 6y = 17
4x + 5y = -5
You can either solve this using elimination or substitution. Let's use elimination. Multiply the top equation by 5, and the bottom equation by 6.
-35x - 30y = 85
24x + 30y = -30
Now, add the equations together. Note the -30y added to +30y will cancel themselves out.
-35x + 24x = 85 + (-30)
-11x = 55
x = -5
To get y, just substitute x = -5 into any one of the equations.
4(-5) + 5y = -5
-20 + 5y = -5
5y = 15
y = 3
x = -5, y = 3
2007-05-30 01:46:51 · answer #3 · answered by Puggy 7 · 0⤊ 0⤋
x= -5 y= 3
2007-05-30 02:21:53 · answer #4 · answered by Anonymous · 0⤊ 0⤋
- 7x - 6y = 17.....(1)
4x + 5y = -5.......(2)
Multipling (1) by 4 and (2) by 7 we get
-28x - 24y = 68
28x + 35y = -35
Adding the above two equations , we get
11y = 33
y = 3
Substituting the value of y in any equation we get ,
x = -5
2007-05-30 01:59:07 · answer #5 · answered by karan 1 · 0⤊ 0⤋
To solve by elimination:
-7x-6y=17 ---> multiply by 5 ---> -35x-30y = 85
4x+5y=-5 ---> multiply by 6 ---> 24x+30y = 30
When you add the two new equations together you get:
11x=55
x = 5
When you substitute 5 in for x into either equation you get:
4x+5y=-5
4(5)+5y=-5
20+5y=-5
5y=-25
y= -5
So, the answer is (5, -5).
2007-05-30 01:49:20 · answer #6 · answered by Jane D 1 · 0⤊ 0⤋
4[-7x - 6y = 17]
7[4x + 5y = -5]
-28x - 24y = 68
28x + 35y = -35
11y = 33
y = 3
4x + 5(3) = -5
4x = -20
x = -5
2007-05-30 01:49:04 · answer #7 · answered by Philo 7 · 0⤊ 0⤋
multiply equation 1 by 4 and equation two by -7
-28x- 24y = 68
-28x -35y = 35
subtract eq 2 from eq 1
-24y+35y = 68-35
11y = 33
y= 33/11 =3
2007-05-30 01:48:36 · answer #8 · answered by K In the House 4 · 0⤊ 0⤋
-7x-6y=17
-6y=17+7x
7x+17=-6y
7x=-6y-17
x=-(6y+17)/7------------(1)
4x+5y=-5-----------------(2)
Substitute (1) into (2),
4[-(6y+17)/7]+5y=-5
-(24y+68)/7+35y/7=-35/7
-24y-68+35y=-35
11y=68-35
11y=33
y=3#
Substitute y=3 into (1)
x=-[6(3)+17]/7
=-[18+17]/7
=-35/7
=-5#
2007-05-30 02:55:21 · answer #9 · answered by jackleynpoll 3 · 0⤊ 0⤋
x = - 805/77 ; y = 103/11
2007-05-31 17:26:26 · answer #10 · answered by FHBLITTLE 1 · 0⤊ 0⤋