Question

What are the zeroes of the function `f(x)=2x+4`?

Answer 1

This function is a straight line, since there is only an `x` term, no `x^2` or higher. That means it only has one zero, which is found as shown below and is `x=-2`.

Explanation:

To find the zero (also called a 'root') we set

`2x+4=0` and solve this equation.

In practical terms this is the point where the line crosses the line `f(x)=0`, which is the x-axis.

`2x+4=0`

`2x=-4`

`x=-4/2`

`x=-2`

Answer 2

`x=-2`

Explanation:

`"the zeros are the value/s of x where "f(x)" crosses"`
`"the x-axis"`

`• " to find the zero set "f(x)=0`

`2x+4=0larrcolor(blue)"solve for x"`

`"subtract 4 from both sides"`

`2xcancel(+4)cancel(-4)=0-4`

`rArr2x=-4`

`"divide both sides by 2"`

`(cancel(2) x)/cancel(2)=(-4)/2`

`rArrx=-2 " is the zero"`
graph{(y-2x-4)((x+2)^2+(y-0)^2-0.04)=0 [-10, 10, -5, 5]}