Question

-14x +15y = 15
21x -20y = -10

Answer 1

solve by?... elimination? substitution? which one?

Answer 2

elimination.

Answer 3

okay so you have to multiply the x or y in both equations so they are the same number

Answer 4

I know :( but I don't nkw what number to multiply.

Answer 5

multiply the top equation by 3 and the bottom equation by 2 and lemme know what you get.

Answer 6

@Rubie you there?

Answer 7

@SmokeysTheName yupp

Answer 8

okay so what did you get ?

Answer 9

what did you get when you multiplied the top equation by 3 and the bottom equation by 2?

Answer 10

wait a minute lemme check.

Answer 11

k

Answer 12

-42x + 45y = 45

Answer 13

42x - 40y = -20

Answer 14

correct (: now you can combine both equations so it would be -42x+42x+45y-40y=45-20
simplify that and tell me what you get

Answer 15

5y = 23

Answer 16

no not quite. you're close, on the right side of the equal sign its 45-20 which equals 25, not 23

Answer 17

therefore you have 5y=25
and from there you can solve for y.
y=..?

Answer 18

y = 5

Answer 19

correct (: now plug y back into the original equation that you started with. you can choose either one, you'll get the same answer.

Answer 20

-16x = -60?

Answer 21

do you chose the -14x+15y=15 equation?

Answer 22

yes.

Answer 23

how did you get -16x

Answer 24

well, -14x + 75 = 15

Answer 25

and then -16x = -60

Answer 26

you dont change -14x . im not sure why you keep changing it.
-14x+75=15
subtract 75 from both sides
-14x=-60

understand?

Answer 27

ohhh okokok

Answer 28

ans is 30/7?

Answer 29

correct (:
or if you put it into decimal its x=4.3

Answer 30

good job @Rubie !! (:

Answer 31

thank oyuu

Answer 32

no problem (: