Algebra Flashcards
(x+y)^2 - (x-y)^2
4xy
(x+y+z)^2
x^2 + y^2 + z^2 + 2(xy + xz + yz)
x^3 + y^3
(x+y)(x^2 + y^2 - xy)
x^3 - y^3
(x-y)(x^2 +y^2 +xy)
T or F. a^n - b^n is always divisible by a- b
T
a^n - b^n is divisible by a+b if
n is even
a^n + b^n is divisible by a+b if
n is odd
How do you express negative exponents ?
reciprocal of the inside base and turn negative to positive exponent
T or F. if 0^x = 0 = 0^y , x is equal to y
False. 0^4 = 0 = 0^3 but 4 ≠ 3
How do you express exponential growth formula?
y(t) = y(0).k^t
T or F. In GMAT, you should always subtract or divide two inequalities
F. You should never
If 0< G < 1 then how does G^n compare to G (if n is odd/even positive integer)
G^n is less than original G
If 0< G < 1 then how does G^n compare to G (if n is odd/even negative integer)
G^n is larger than original G
If -1< G < 0 then how does G^n compare to G (if n is odd/even positive integer)
G^n is larger than original G
If -1< G < 0 then how does G^n compare to G (if n is odd/even negative integer)
G^n is larger than original G (if n is even)
G^n is smaller than original G (if n is odd)
T or F. If both sides are known to be negative, you can’t flip the inequalities sign when you square
False. You can flip the sign.
Ex: -4 < - 3 then 16 > 9
T or F. If both sides are known to be positive, you don’t flip the inequalities sign when you square
True.
T or F. If one side is positive and one side is negative, the inequality sign stays when you square
False.
it may or may not
T or F. If the signs are unclear, then you cannot square
True.
If x < y, then how does 1/x compare to 1/y when x and y are both positive or both negative?
1/x > 1/y (flip the sign)
If x < y, then how does 1/x compare to 1/y when x is negative and y is positive?
1/x < 1/y
T or F. If you don’t know the sign of x or y, you can still take the reciprocals.
False.
if |x| > a then:
x > a or x < -a
if |x| < a then:
-a < x < a
If |A| = |B| then
A = B or A = - B
What is the equation expression for directional proportionality?
y(1)/ x(1) = y(2)/ x(2)
What is the equation expression for inverse proportionality?
y(1) . x(1) = y(2) . x(2)
When 0< G < 1, G^n < G if
n is positive integer