Thread: Quadratic functions

I got a maths test today, but I only found out this morning that we have to learn about these, too! And I don't get the second half of this example. We're learning about Quadratic functions (well, slopes and stuff), and this is what the book's example says.

Find, in slope-intercept form, the equation of the line through (-1,3) with a slope of 5.

Then the example goes like this :

y - 3
____ = 5
x - -1


I.E.

y - 3
______ = 5
x + 1


Therefore : y - 3 = 5 (x + 1)

And now, this is the part I don't get.

y + 3 = 5x + 5

Where does that 5 come from

5(x+1) = 5*(x+1) = 5*x + 5*1 = 5x + 5

Originally Posted by Peritus

5(x+1) = 5*(x+1) = 5*x + 5*1 = 5x + 5

What does the * stand for? :O

Originally Posted by Hikaru

What does the * stand for? :O

It stands for 'times' as in 'multiplication'.