Hence displacing the point ( 3, -1) against (x,y)
y -- 1 = -3(x - 3) / 2
y + 1 = -3x/2 + 9/2
y = -3x/2 + 7/2
2y = -3x + 7
3x + 2y = 7
2.
4Cos3x + 7 = 6
You do not specific if he '+7' is under the Cos function or not.
However
Assuming it is under the cos function
then
Cos(3x + 7) = 6/4 = 3/2 = 1.5
This will not resolve as Cos functions cannot range outside the limits of '-1 to +1'.
However,
4Cos3x + 7 = 6
4Cos 3x = -1
Cos 3x = -1/4
3x = Cos^-1( - 1/4)
3x = 104.47751218592992387877103479913 degrees
3x = 104.5 degrees (Nearest tenth).
x = 104.5 / 3
x = 34.8333.. degrees.
3.
y = 2x^2 - 8x
dy/dx = 4x - 8 Is the slope any point 'x'.
Substituting in x = 3
4(3) - 8 = 12- 8 = 4
Hence '4' is the slope.