HELP ME.. please? (1 Viewer)

[_shygirl]

i'm in year 10 but i was put in the year 11 math class (2 unit)... dont laugh at me but i`m really dumb, i have no idea how i got band 5 for the SC.. we`re doing parabolas now, and i have no idea how to sketch a graph.. how do you find the vertex? i know for the X coordinates, it's -B/2a, whats A and whats B? the question is: sketch y= -2x² THANKS

 

[redruM]

y= A.x^2 + B.x + C

general form of the parabola.

in your case, A = -2, B = 0.

.'. x-coordinate of vertex: x=0
.'. y-coordinate of vertex: y=0

so, it will just be an upside down parabola with vertext at the origin.

a little extra: would you know what to do if it said graph y= -x^2 on the same set of axis?

 

[velox]

i know how u feel atm, i feel the same
Or to find the y co-ordinate u can just use the -b/2a and then sub in that value into the equation to get the y value.