I don't understand what I'm doing wrong, please help

Answer:
dy/dx= 7- 3x^-1/2
when X=1
dy/dx = 4
as it is a tangent M1=M2=4
now,
at gradient 4 and point (1,1)
equation of curve is ,
y-y1= m(x-x1)
or, y-1=4(x-1)
or, y-1=4x-4
or, y-4x= -3
or, 4x-y=3
Answer:
BRAINLEST ANSWER
Step-by-step explanation:
dy/dx=7-3x^-1/2
when x=1
Dy/dx=4
as it is a tangent M1=M2=4 now
at gradient 4 and point(1,1) equation of a curve is y-y1=m(x-x1)
or y-1=4(x-1)
or y-1=4x-4
or y-4x=-3
or 4x-y=3