Question

抛物线y=3ax²-2bx+1 经过点(1,-2)(-2,3) 求3a²-2b²的值

Answer 1

y=3ax^2-2bx+1

y(1)=-2

-2= 3a-2b+1

3a-2b = -3 (1)

y(-2)=3

3=12a+4b-1

3a+b=1 (2)

(1)-(2)

3b=4

b=4/3

a=-1/9

3a^2-2b^2

=1/27 - 32/9

=-95/27