How do you graph 2x+5y=10 using intercepts?

2 Answers
Mar 19, 2017

Graph of y=-2/5x+2
graph{-2/5x + 2 [-7, 7, -7, 7]}

Explanation:

The equation of a straight line with gradient m and y-intercept c is:

y=mx+c

You have been given all the information you need but to get to this format, need to rearrange:

2x+5y=10

subtracting 2x from each side gives

-2x+2x+5y=10-2x

5y=-2x+10

Dividing through both sides by 5 gives

(5y)/5=(-2x)/5+10/5

y=-2/5x+2

So now it can be seen that the y-intercept is 2 and the gradient is -2/5.

The x-intercept can be found when y=0:

0=-2/5x+2

To find the value of x this again needs rearranging:

0+2/5x=-2/5x+2+2/5x

2/5x=2

2/5x xx5/2=2xx5/2

x=10/2=5

So the x-intercept is at 5.

This means that the graph will cross through:

the x-intercept (0,5); and

the y-intercept (2,0).

You can mark these on your graph and then draw a line through them both.

Graph of y=-2/5x+2
graph{-2/5x + 2 [-7, 7, -7, 7]}

Mar 19, 2017

see explanation.

Explanation:

To find the intercepts.

• " let x = 0, in the equation, for y-intercept"

• " let y = 0, in the equation, for x-intercept"

x=0to0+5y=10toy=2larrcolor(red)" y-intercept"

y=0to2x+0=10tox=5larrcolor(red)" x-intercept"

Plot the points (0 ,2) , (5 ,0) and draw a straight line through them. This is the graph of 2x + 5y = 10
graph{-2/5x+2 [-10, 10, -5, 5]}