6x +y = -15 and 4x - 5y = 7. Use substitution to solve this linear system...?

Question

I don't understand solving Linear Equations by algebra. Any help would be appreciated.

Answer 1

6x +y = -15 .......(1)
4x - 5y = 7..........(2)

Multiply (1) by 5
30x+5y=-75

Add this with (2)
34x=-75+7=-68
x=-68/34 = -2

Put it in (1)
6*(-2)+y=-15
-12 + y = -15
y=-15+12
y= -3
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if you want to use substitution method,
from (1) y=-15-6x
Put this value of y in (2)
4x -5(-15-6x)=7
4x+75+30x=7
34x=7-75=-68
x=-68/34
x= -2

rest is same as done above.

Answer 2

6x + y = -15 4x - 5y = 7 enable 6x + y = -15...eq1 4x - 5y = 7...eq2 using eq1, transpose 6x to acquire y = -15 - 6x... you have observed that to procure the y on my own... now, exchange this y in eq2 to acquire 4x - 5(-15 - 6x) = 7 distribute -5 on (-15 - 6x) to acquire 4x + seventy 5 + 30x = 7 combine like words to acquire 34x = -sixty 8 divide the two facets by using the coefficient of x it is 34 to acquire x = -sixty 8/34 x = -2.............answer

Answer 3

6x + y = -15 -> y = -15 - 6x

4x - 5y = 7
4x - 5 (-15 - 6x) = 7
4x + 75 + 30x = 7
34x = -68
x = -2

6(-2) + y = -15
-12 + y = -15
y = -3

x = -2, y = -3

Answer 4

X = 41/17

Answer 5

y = - 6x - 15
4x - 5(- 6x - 15) = 7
4x + 30x + 75 = 7
34 x = - 68
x = - 2
y = 12 - 15
y = - 3
Solution is x = - 2 , y = - 3

Answer 6

isolate x or y so youd wanna isolate y in the first one so rearrange:

y= -15 - 6x and 4x -5y=7

then you just sub in y=- 15 - 6x for every y u see so:

4x-5(-15-6x)=7

4x +75 + 30x= 7

34x +75= 7

34x=82

82 divide by 34 = (cant do it off top of my head)

Answer 7

6x+y=-15........1
4x-5y=7...........2
from 1
6x=15-y.........3
x=15-y/6
sub 3 into 1

4(15-y/6) t y=-15
30-2y/3 +y =-15
30-2y+3y/3=-15
30-y/3=-15
30-y=-45
-y=-45-30
-y=-75
y=75
sub when y=75 into 1
6x+75=-15
6x=-15-75
6x=-90
x=-90/6
x=-15
thereforex=-15,y=75

Answer 8

yes Use substitution to solve this linear qns.

Answer 9

sammi, is this due tomorrow?

I can show you how to solve this

but then you won't learn your lesson about putting things off at the very last minute to do your homework

Answer 10

y=-15-6x
-5y=75+30x
4x-5y=4x+75+30x=7
34x=-68
x=-2