For what values of y does y^2-2y=48? Show all work.

Question

amistre64 · Answer

-6 and 8

anonymous · Answer

How did you get that?

anonymous · Answer

he is super fast that is how.  plus wolfram

anonymous · Answer

$$y^2-2y-48=0$$
$$(y+6)(y-8)=0$$

amistre64 · Answer

sometimes I feel like working it out; others times not lol

anonymous · Answer

$$y+6=0$$
$$y=-6$$
$$y-8=0$$
$$y=8$$

anonymous · Answer

method two
$$y^2-2y=48$$
$$(y-1)^2=48+1=49$$
$$y-1=7$$ or $$y-1=-7$$
$$y = 8$$ or $$y=-6$$

anonymous · Answer

pfft super fast , anyone thats been doing maths for like 4yrs should be able to solve a quadratic like that in about 30seconds

anonymous · Answer

its even monic which makes it even easier!

amistre64 · Answer

28.6875378583032847459504348475... secs lol

amistre64 · Answer

30 seconds is for my grandma ;)

anonymous · Answer

i still cannot factor to save my life.  prefer to find the zeros

amistre64 · Answer

the factors are just the zeros in reverse;

if x = -3, 5 are roots then

(x+3)(x-5) are the factors

amistre64 · Answer

maybe should ammend that to have a constant of variation, but you know lol

anonymous · Answer

of course and so to factor i find the zeros.  it is easier for me to do it that way

anonymous · Answer

Satelite, thanks for the tip about wolfram. It calculated the answer to "life, the universe, and everything" super-fast !