Question

How do you write the linear function whose x intercept a and y intercept b are given: a=3 b=4?

Answer 1

`y=-4/3 x+4`

Explanation:

Standard form equation: `y=mx+c`

`color(blue)("To find the gradient")`

`m-> "gradient"-> ("change in y")/("change in x")->(y_("end point")-y_("start point"))/(x_("end point")-x_("start point"))`

`color(blue)(m=(0-4)/(3-0) = -4/3)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("To find the value of the constant c")`

They told us what it is in the question!
It is where the plotted line crosses the y-axis and they said that the y intercept =b = 4

`color(blue)(c=4)`
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
`color(blue)("Putting it all together")`

`y=mx+c ->color(blue)( y= -4/3x+4)`