Question

By using substitution:
15x+3y=5
5x+y=-6
Show me how to do this.

Answer 1

Let's manipulate the second equation, we'll get it in terms of y=, and then we'll PLUG it into the first equation.
\[\large 5x+y=-6\]Subtracting 5x from both sides gives us,\[\large y=\color{cadetblue}{-6-5x}\]We want to plug this in for the y in the other equation.\[\large 15x+3\color{cadetblue}{y}=5\]
Which gives us,\[\huge 15x+3\color{cadetblue}{(-6-5x)}=5\]

Answer 2

We SUBSTITUTED one equation into the other one.
From here it's not too bad. We just have to multiply the 3 by each term in the brackets, and then solve for x.

If you're still confused, let me know.

Answer 3

Okayy I will,

Answer 4

See this
http://openstudy.com/study#/updates/50d0ff5ce4b0091849d7a6f6

Answer 5

@nickersia Oh thanks.