Question

How do you solve `0.1x + 0.6y = -1` and `0.2x - 0.7y = 3.7` using substitution?

Answer 1

`x=-3`
`y=-7/6`

Explanation:

`0.1x+0.6y=-1`
Multiplying both sides by 10 we get
`x+6y=-10`
Similarly multiplying both sides of `0.2x-0.7y=3.7`by 10
we get
`2x-7y=37`
Similarly multiplying both sides of `x+6y=-10` by `2`
we get
`2x+12y=-20`
Subtracting `2x-7y=37` from `2x+12y=-20`
we get
`2x+12y-2x+7y=-20-37`
or
`19x=-57`
or
`x=-57/19`
or
`x=-3`------------Ans`1`

Since from above we have Equation `x+6y=-10`
By putting value of x=-3 in the above equation we get
`-3+6y=-10`
or
`6y=-7`
or
`y=-7/6`------------Ans`2`