Review for PreCal? Help!?

Question

Change the following equation into graphing form by completing the square y = x^2 + 8x - 11

For the following equation state the maximum/minimum point, the parent graph, and whether the graph is getting wider or narrower y = -2(x+3)^2 - 7

Find the line perpendicular to 3x + y = 5 and through the point (4,1).

Could you guys help me out?? Thanks so much :)

Answer 1

I can't remember how to do the first two, but I do remember the third:

Perpendicular lines have the same slope, but different y intercepts, so you have to put the equation you have now into slope-intercept form:

Y = - 3x + 5

Now, you have to rewrite that equation with an "b" intercept:

Y = - 3x + b

Plug in X and Y to solve for b:

1 = -3 (4) + b

1 = -12 + b

13 = b

Put b back into the equation:

Y = -3x + 13

We did those problems in PreAlg and Algebra when I was in 6th a 7th, so I don't really remember how to do the first two.

I hope this helps!