Simplifying Rational Expressions?

Question

1: A Rational expression is
an undefined fraction
a quotient of polynomials
a polynomial with 3 terms


2: When is a fraction undefined?
When its numerator equals 0.
When its denominator equals 0.
When it simplifies to 1.


3: Which answer makes the following undefined?

14/x-2

x=

a) -2
b) 2 or -2
c) 2

4.

5-x/x^2-4

a) -2
b) 2 or -2
c) 2

5.

16/x^2 - 2x - 15
x=

a) -3 or 5
b) 6
c) -2 or 7

Answer 1

1 (b)
2 (b)
3 (c)
4 (b)
5 (a)

Answer 2

(1) not really any of the above ...

The second is best ... a ratio of polynomials

(2) When its denominator equals 0

(3) c when x = 2 (and hence x-2 = 0 and so 14/0 is undefined)

(4) b when x = 2 or -2 (and hence x^2-4 = 0)

(5) a when x = -3 or 5 (these are the zeros of the quadratic)

Answer 3

2) Denominator=0

3) x=2

4) x=2 or x=-2

5) factor bottom to (x+3)(x-5) thus -3 or 5 will make denom 0.