Question

PLEASE i need help solving these systems by using substitution. (HELPER WILL GET A METAL)
-8x-9y=26
-3x-y=24

Answer 1

Try this :

first, copy down the first equation.
Next, multiply the second equation by 9 and write it immediately below the first.
Does this result give you an idea of what to do next to solve this system of linear equations by elimination?

Answer 2

substitution means that you put one variable into the other equation.
That is: solve one for x or y, and then plug x or y into the other.

Answer 3

If you are to use substituion, then decide which equation is easier to solve for either x or y, and then solve it for x or y. substitute the result into the other equation.

Answer 4

yeah, i rearranged the second equation

Answer 5

do i plug it into y?

Answer 6

of the first equation?

Answer 7

\[-8x-9y=26-First~eqn\]\[-3x-y=24-Second~eqn\]\[y=-3x-24-Third~equation\]Use the third equation to substitute into the first equation

Answer 8

\[-8x-9(-3x-24)=26\]

Answer 9

\[-8x+27x+216=26\]

Answer 10

Then subtract both sides by 216

Answer 11

\[-8x+27x=26-216\]

Answer 12

\[19x=-190\]Then divide both sides by 19

Answer 13

wait i thought the 3 became negative?

Answer 14

\[\frac{ 19x }{ 19 }=-\frac{ 190 }{ 19 }\]\[x=-\frac{ 190 }{ 19 }\]

Answer 15

scuse me positive

Answer 16

If you "rearranged the second equation," then y our -3x-y=24 became -3x+3x-y=24+3x, or -y=24+3x. Next, solve this last result for y. I always want to see the actual results you've gotten.

Substitute y=-24-3x into the first equation, if y ou haven't already done so.
(MARC has done this.)

Find x. Then, again using substitution, find y.

Finally, check your solutiion (x,y) in both equations to determine whether it satisfies both.

Answer 17

\[x=-10\]Then substitute x=-10 into the second eqn to solve for y

Answer 18

\[-3(-10)-y=24\]

Answer 19

\[30-y=24\]Then subtract 30 on both sides

Answer 20

\[30-30-y=24-30\]\[-y=-6\]Lastly,divide both sides by -1

Answer 21

\[\frac{ -1 }{ -1 }y=\frac{ -6 }{ -1 }\]

Answer 22

\[y=?\]solve it @arbyj

Answer 23

i got 6

Answer 24

Very good your right,

Answer 25

thank you all for your help :) goodnight

Answer 26

Please be certain to label each coordinate. Do you mean x=6, or do you mean y=6?

Once you have a possible solution, please check it by substitution into the original equations. if both equations come out TRUE, then you have a solution. If not, .... :(

Answer 27

y=6

Answer 28

You don't have a solution until you've found both x and y and have checked your x and y into both of the original equations.

Answer 29

-10,6