-50 + 2a if a = 2.5 write the meaning of each algebraic expression then evaluate it for the given value I have no idea what this means please help

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

Can someone check if i did this correct. it’s number 4 if you’re wondering.

What will the graph look like for a system of equations that has no solution? a. the lines will be perpendicular. b. the lines will cross at one point. c. both equations will form the same line. d. the lines will be parallel.