Step-by-step explanation:
they're is a neat little trick.
but first of all, "roots" means the 0 solutions of the equation. like
ax² + bx + c = 0
there are 2 solutions for x to make the whole expression equal 0.
these are the "roots".
now to the little trick :
when is a multiplication resulting in 0 ?
when at least one of the factors is 0.
and any quadratic expression can be written as multiplication of 2 factors. like
c(x - a)(x - b) = cx² - cax - cbx + cab
what are the "roots" or 0 points ?
either
c = 0
x - a = 0 | x = a
x - b = 0 | x = b
the leading coefficient = 3.
that means nothing else than c = 3.
root = 1 means (x - 1) is one factor.
root = -5 means (x + 5) is the other factor.
so, we have
3(x - 1)(x + 5) = 3x² + 12x - 15
and the equation is
3x² + 12x - 15 = 0
or
3x² + 12x = 15
10x + 40 = 100
A restaurant owner sells each plate of rice for 10 dollars plus an additional 40 dollars for the entrance. Mack goes to that restaurant and pays 100 dollars in total. How much plates of rice did he order?<span />
Answer:
182.88cm
Step-by-step explanation:
i looked it up
Answer:
-1,2
Step-by-step explanation:
# of boys : # of girls
This can be written as
6:15
6 to 15, or
6/15
