F(x)=-3x+4, slove for a when f(x)=1

i agree because i see the other persons thinking is clear

the image is given below

since the options are not given so we draw it from the equation

the given equation is

y = (x-1) (x+4)

y = y² + 3x - 4

the above equation is a quadratic equation which will have two roots. if we draw the graph for it, it will look like this