It is known that the image of a function passes through two points (3,5) and (- 4, - 9), and (1) the analytic expression of the function is obtained. (2) if the point (a, 2) is on the function image,

It is known that the image of a function passes through two points (3,5) and (- 4, - 9), and (1) the analytic expression of the function is obtained. (2) if the point (a, 2) is on the function image,

(1) (3,5) (- 4, - 9)
Substituting y = KX + B
①5=3k+b
② -9=-4k+b
From (1) to (2), it is concluded that
14=7k
k=2
Substituting k = 2 into (1)
5=3X2+b
b=-1
So y = 2x-1
(2) If point (a, 2) is on the function image
2=2a-1
a=3/2