Friday, August 28, 2015

`0.5x + 3.2y = 9.0, 0.2x - 1.6y = -3.6` Solve the system by the method of substitution.

Multiply everything by 10 to get whole numbers



Solve equation [2] for the variable  x 
 


`2x = 16y - 36`

`x = 8y - 18`

Plug this in for variable  x  in equation [1]


`5(8y-18) + 32y = 90`
`72y = 180`

Solve equation [1] for the variable  y 


`72y = 180`

`y = 5/2`

By now we know this much :


`x = 8y-18`
`y = 5/2`

Use the  y  value to solve for  x 


`x = 8(5/2)-18 = 2`

The solution is `(2,5/2)`

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