How do you graph #y=x^2+4x-3#?

1 Answer
Bugatti S.
Apr 19, 2018

Check explanation

Explanation:

So, as you can see the x2 has no negative in front of it. This lets you know that the graph has a minimum and not a maximum. You can find the y-intercept by substituting x with 0.

You can find the x-intercept by solving the equation for x. This is a quadratic equation and therefore you will have 2 points where the graph intersects the x-axis.

0 = x2 + 4x - 3
You can use the formula;

#(b +- sqrt(b^2 - 4ac))/(2a)#

Therefore x-intercepts: (#sqrt7 - 2#, 0) and (#-2-sqrt7#, 0)
Therefore y-intercept: (0, -3)

If you want to go further, you can figure out the minimum point by using the formula;

#-b/(2a)# for the x value
and #(4ac-b^2)/(4a)# for the y-value

ELSE, if you did not understand anything i just said, you can always used a defined range (say for example from x = -4 to x = 4) and find their respective y-values and plot in that way.

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