How do I write these parabolas in vertex form? focus at (4, 3), and directrix x = 2
focus at (2, -1), and directrix x = 8

Find the gradient of f(x, y,z)equals=left parenthesis x squared plus y squared plus z squared right parenthesis superscript negative 1 divided by 2 baseline plus ln left parenthesis x right parenthesis x2+y2+z2−1/2+ln(xyz) at the point left parenthesis negative 2 comma 1 comma negative 2 right parenthesis(−2,1,−2).

Find the magnitude, correct to two decimal places, made by each of the following with positive direction of the x axis a) y= x the answer is 45° but i don’t know how

At a book fair, joe bought 24 books at 3 for $5 and had $2 left. how much money did he have at first?