In three dimensions, the cross product of two vectors is defined as shown below

Then, solving the determinant

In our case,

Where we used the formula for AxB to calculate ixj.
Finally,

Thus, (i+j)x(ixj)=i-j
I don’t have a calculator right now but a triangle always adds up to 180 degrees so yeah
Answer:
Step-by-step explanation:
LOL The graph doesn’t match the y intercept :)
Anyway
If we have point (0,-3) we have a quadratic of
y=ax^2+bx-3 we are given points (-1,0) and (2,0) so
a-b-3=0 and 4a+2b-3=0
4a+2b-3+2(a-b-3)=0
4a+2b-3+2a-2b-6=0
6a-9=0
6a=9
a=1.5, since a-b=3
1.5-b=3
b=-1.5
y=1.5x^2-1.5x-3