Question

For each question, find y when x=-3Then find x when y=21. For y=6x+8; y=___ and x=____ 2. For y=2/3x; y=____ and x=____3. For y= -x+5; y=____ and x=____4. For y=3/4x-2 1/2; y=_____ and x=____5. For y= 1.5x+11; y=____ and x=____

Answer 1

We have the expression

`y=(3)/(4)x-2(1)/(2)`

If x=3, then the expression takes the value:

`\begin{gathered} y=(3)/(4)(3)-2(1)/(2) \\ =(9)/(4)-(5)/(2) \\ =(18-20)/(8) \\ =(-2)/(8) \\ =-(1)/(4) \end{gathered}`

Now, if y=2 then:

`\begin{gathered} 2=(3)/(4)x-2(1)/(2) \\ 2+2(1)/(2)=(3)/(4)x \\ 2+(5)/(2)=(3)/(4)x \\ (4+5)/(2)=(3)/(4)x \\ (9)/(2)=(3)/(4)x \\ x=((4)/(3))((9)/(2)) \\ x=(36)/(6) \\ x=6 \end{gathered}`