R Flashcards
Quadratic Formula
x = -b +/- √(b^2 - 4ac)
/ 2a
If b^2 - 4ac is equal to 0, how many solutions?
One solution.
If b^2 - 4ac is positive, how many solutions?
Two solutions.
If b^2 - 4ac is negative, how many solutions?
No solution.
An integer is divisible by 3 if the sum of the integer’s digits…
is divisible by 3.
A number is divisible by 4 if
it’s simply divisible by 2 twice, or
if the last two digits are divisible by 4.
An integer is divisible by 6 if
it’s divisible by both 2, and 3 (sum of digits are divisible by 3).
An integer is divisible by 8 if
the last 3 digits are divisible by 8 (divisible by 2 three times)
An integer is divisible by 9 if
the sum of the integer’s digits is divisible by 9
Factor Foundation Rule
If a is a factor of b, and b is a factor of c, then a is definitely a factor of c.
Even x even
Even
Even x Odd
Even
Odd x Odd
Odd
Even + Even
Even
Even + Odd
Odd
