we have
Write a quadratic equation in standard form whose graph passes through the given points (1,2) (2,-1) (3,-6)
A quadratic equation in standard form is equal to
y=Ax^2+Bx+C
substitute the given values
(1,2)
2=A(1^2)+B(1)+C
2=A+B+C ------> equation 1
(2,-1)
-1=A(2^2)+B(2)+C
-1=4A+2B+C -------> equation 2
(3,-6)
-6=A(3^2)+B(3)+C
-6=9A+3B+C -------> equation 3
step 1
In the equation 1 isolate the variable A
A=2-B-C -------> equation 4
step 2
substitute equation 4 in equation 2 and 3
-1=4(2-B-C)+2B+C
-1=8-4B-4C+2B+C
-1=8-2B-3C
2B+3C=
