Question

What is the solution to the system of equations
5x-3y=-9
2x-5y=4

Answer 1

I also need help on that too can any one help me please?

Answer 2

and me :P

Answer 3

ohh and me!! xp

Answer 4

Do you know substitution or elimination?

Answer 5

yes partially

Answer 6

Which do you want to use?

Answer 7

umm im not sure :P

Answer 8

5x-3y=-9
2x-5y=4

2(5x-3y)=-9*2
10x - 6y = -18

-5(2x-5y)=4*-5
-10x + 25y = -20


10x - 6y = -18
-10x + 25y = -20
----------------------------
0 + 19y= -38

19y/19 = -38/19
y = -2


Now we know y = -2. Take -2 and put it into one of the other equations and solve for x.

5x-3(-2)=-9

Can you finish and find x?

Answer 9

Elimination
Take note of the coefficients of \(x\)\[
\color{red}5x-3y=-9\\
\color{blue}2x-5y=4
\]Multiply the equations so that they are the same: \[
\color{blue}2\cdot(\color{red}5x-3y=-9)\\
\color{red}5 \cdot (\color{blue}2x-5y=4)
\]Then it becomes: \[
10x-6y=-18\\
10x-25y=20
\]Now you can subtract the second equation from the first: \[
(-6-(-25))y = -18 -20\\
19y=-38
\]Now you can solve for \(y\)\[
y=-2
\]Then put that into the equations above: \[
5x-3(-2)=-9
\]And you can solve for \(x\).

Answer 10

sorry it wouldnt load... but would I do the same thing for the first one?

Answer 11

for the second one I mean

Answer 12

What second one?

Answer 13

for x

Answer 14

.... :/

Answer 15

Well, you have to isolate \(x\).

Answer 16

\[
5x+6=-9
\]Move the \(6\) over: \[
5x=-15
\]So... what times \(5\) is \(-15\)?

Answer 17

3

Answer 18

so (-2, 3)

Answer 19

@Jackky @lopez09

Answer 20

idk any of this srry im startin to learn it

Answer 21

(-2, 3)

Answer 22

or at least thats what I think it is but @wio hasn't said anything yet

Answer 23

You can always plug it into both equations to see if it is true

Answer 24

However, \[
5(3) = 15\neq -15
\]

Answer 25

\[
5x=-15\\
x = \frac{-15}{5}=-3
\]

Answer 26

so negative 3 not 3

Answer 27

@wio

Answer 28

Yes

Answer 29

thank you