Both represent where the graphs cross the y-axis. This value is called the y-intercept.
The quadratic equation [tex]y=a x^{2} +bx+c[/tex] is used to represent a quadratic relationship, and if you replace x with 0 which is how you find the y-intercept, the result is y = c.
Example:
[tex]y=5 x^{2} +3x-4[/tex]⇒[tex]y=5(0)^2+3(0)-4[/tex]⇒[tex]y=-4[/tex]
The linear equation [tex]y=mx+b[/tex] is used to represent a linear relationship, and if you replace x with 0 which is how you find the y-intercept, the result is y = b.
Example:
[tex]y=4x-7[/tex]⇒[tex]y=4(0)-7[/tex]⇒[tex]y=-7[/tex]
