## brandoduh 3 years ago Solve using substitution 2x=y+9 5y=10x-45

1. lgbasallote

if 2x = y + 9 then let y = 2x - 9 make sense?

2. brandoduh

no really :/

3. gypsi

find one variable, either x or y, first

4. brandoduh

i think ill choose x

5. gypsi

so if you get x alone for one equation, you then replace what you get into the second equation and solve for y

6. brandoduh

so i mutiply 10x on all 3 of the first equation?

7. gypsi

o.O? to get x alone? or?

8. brandoduh

to subtract it with the other equation?

9. gypsi

are you trying to solve it by elimination?

10. brandoduh

no by substitution

11. gypsi

if you get Y alone in the first equation it would be what the first person said y=2x-9 then you substitute the 2x-9 into the second equation getting 5(2x-9)=10x+45

12. gypsi

10x-45=10x-45*

13. brandoduh

oh i kinda get it. then you multipy 5 on the parantesis

14. brandoduh

15. gypsi

both sides equal each other if you combine like terms you get 0=0

16. brandoduh

:o o? wow. now i have to solve the other 1

17. gypsi

good luck! hope it helped.

18. brandoduh

its sure did friend=)