Question

How do you solve `15x-20y=1` and `10y=1+5x` using substitution?

Answer 1

`x=3/5` and `y=2/5`

Explanation:

We have two equations `15x-20y=1` and `10y=1+5x`. Here we can easily substitute the value of `10y` from the second equation into the first equation and doing so we get

`15x-20y=1`

`15x-2xx10y=1`

`15x-2×(1+5x)=1` or

`15x-2-10x=1` or

`15x-10x=1+2` or

`5x=3` and `x=3/5`.

Hence `10y=1+5x`

= `1+5×3/5=1+3=4` or

`y=4/10=2/5`