Question

A general formula for a parabola is y2 = 4px. What is the value of p in the equation y2 = –4x?

Answer 1

Easy

compare
y²=4px vs
y²=-4x

y²=y²
4px=-4x
divide both sides by x
4p=-4
divide both sides by 4
p=-1




p=-1

Answer 2

Answer:

p= -1

Explanation:

We have been given parabola along positive side of x-axis with equation

$y^2=4px\\\\and\\\\y^2=-4x$

after equating the values of $y^{2}$  we will get

4px =-4x

Divide each term by x on both left hand side and right hand side  we will get

4p= -4

Now, divide each term by 4 on both left hand side and right hand side we will get the final result p=-1