What is y2-28 equals 3y?

Answer 1

so the problem looks like this:

y2 - 28 = 3y

if you notice... this is a polynomial... (just a fancy word to say there is a "y2 " thing in your equation... which is also known as a quadratic equation)

whenever you see a quadratic equation and a equal sign you want to set you quadratic equation = to zero.

that means you want to minus both sides of your equation by 3y

so now your equation will look like this:

y2 - 3y - 28 = 0

(I put the minus 3y in front of the negative 28 because I want to put it in descending order.)

from there you want to find factors of 28

so some factors are:

1,28

4, 7

well since we want 2 numbers that multiply to make a NEGATIVE 28 one of your numbers has to be negative and the other has to be positive.

and since your middle term in the equation is a NEGATIVE 3 that means whatever your numbers that break down to give you 28... when you add them together they MUST equal a NEGATIVE 3.

in this case

your 7 would have to be negative and your 4 would have to be positive.

heres a way to check:

4 x -7 = -28

-7 + 4 = -3

sooo with that being said you set up your parenthesis

(x + 4) (x - 7) = 0

(DONT FORGET YOU HAD TO EQUAL IT TO ZERO)

when you equal it to zero that means you must set both of whatever is inside your two sets of parenthesis to zero... in this case

x+4=0 and x-7=0

when you do your algebra

you should get x=-4 and x=7

*tip: if you have something like this question and it is relating to an object that has sides... like a triangle, square.... etc. your answer will be ONLY positive 7 because you cannot have negative sides :)

sorry Im just trying for you to get the concept.