How do you graph the equation by plotting points #y=x^2-9#?

Question

2566 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-07-16T15:07:26

Please see below.

Observe that when #x=0#, we have #y=-9#.

This means two things -

(1) Point #(0,-9)# lies on the curve and

(2) this is the minimum value of #y# and as #x# moves on either side of #x=0#, #y# rises from its value of #-9#.

When #x=+-2#, #y# is #-5#, when #x# is #+-4#, #y# is #7#

when #x=+-6#, #y# is #27#

This means curve passes through #(2,-5),(-2,-5),(-4,7),(4,7),(-6,27)# and #(6,27)#

Joining them we get the curve as follows:

graph{x^2-9 [-41.83, 38.17, -11.04, 28.96]}