{x = -4y - 9
{-5x + 3y = -1
a. (1, -1)
b. (-2, -1)
c. (-1, -2)
d. no solution
2007-12-04 03:59:32 · 8 answers · asked by . 1 in Science & Mathematics ➔ Mathematics
1) x = -4y - 9
2) -5x + 3y = - 1
Substitute from eq 1 into eq 2
-5(-4y - 9) + 3y = -1
20y + 45 + 3y = -1
23y = - 46
y = -2
x = -4(-2) - 9
x = 8 - 9
x = -1
Check
-5(-1) + 3(-2) = - 1
5 - 6 = -1
-1 = -1
2007-12-04 04:06:11 · answer #1 · answered by Anonymous · 1⤊ 0⤋
The first equation already express x in terms of y so subsitute it for x in the second equation:
-5x +3y = -5*(-4y-9)+3y = -1
20y +45 +3y =-1
23 y = -46
y = -2
Then x = -4y-9 = -4*(-2) -9 =-1
So c is the correct answer
2007-12-04 04:07:02 · answer #2 · answered by nyphdinmd 7 · 1⤊ 0⤋
Let's use substitution since we already know what x equals in terms of y:
x = -4y - 9
Put this in for x in the second equation:
-5x + 3y = -1
-5(-4y - 9) + 3y = -1
20y + 45 + 3y = -1
23y = -46
y = -2
Now put -2 for y in either equation:
x = -4y - 9
x = -4(-2) - 9
x = 8-9
x = -1
(-1, -2) which is c
Best of luck! :)
2007-12-04 04:06:24 · answer #3 · answered by disposable_hero_too 6 · 1⤊ 0⤋
Given
x= - 4y - 9 .........................(1)
-5x+3y= -1 ........................(2)
put the value of x from equation (1) to (2)
-5(-4y-9)+3y= -1
20y+45 +3y = -1
23y +45 = -1
23y= -46
y= -46/23
y= -2
put the value of y in equation (1)
x = -4(-2) - 9
= 8 - 9
x= -1
c (-1,-2)
The solution is c(-1,-2)
2007-12-04 04:19:06 · answer #4 · answered by dinky 2 · 1⤊ 0⤋
Substituting the value of x in the second equation we get:
-5(-4y-9) + 3y = -1
:. 20y + 45+3y= -1
:. 23y= -46
:. y = -2
Substituting the value of y in the first equation we get:
x= -4(-2) -9
:. x= 8-9
:. x= -1
Therefore, correct answer is (c).
P.S. Hope this helps.
2007-12-04 04:15:49 · answer #5 · answered by Vaibhs >> 2 · 1⤊ 0⤋
Take the first equation and plug it in the second equation for x:
-5(-4y-9)+3y=-1
20y+45+3y=-1
23y+45=-1
23y=-46
y=-2
x=-4(-2)-9
x=8-9
x=-1
The answer is c.
2007-12-04 04:46:59 · answer #6 · answered by Anonymous · 0⤊ 0⤋
2x + 4y = sixteen equation I 3x - 5y = fifty 4.8 equation II (I)2x = sixteen - 4y x = (sixteen - 4y):2 x = 8 - 2y Substitution: (II) 3(8-2y) - 5y = fifty 4.8 24 - 6y - 5y = fifty 4.8 -11y = fifty 4.8 - 24 -11y = 30,8 y = -2.8 x = 8 - 2(-2.8) x = 8 + 5.6 x = 13,6 Resposta: (13,6 e -2,8)
2016-12-10 12:19:52 · answer #7 · answered by ? 4 · 0⤊ 0⤋
-5(-4y - 9) + 3y = -1
20y + 45 + 3y = -1
23y = -46
y = -2
x = -1
Kindrick, THANKS!
2007-12-04 04:05:32 · answer #8 · answered by Hiker 4 · 1⤊ 1⤋