Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Year 12s: what will be the first way you research your future options? >>

Have I done this correctly?

http://prntscr.com/b0751l

\frac{4}{x(x+3)}+\frac{5}{x+3} = \frac{4}{x(x+3)}+\frac{5x}{x(x+3)} = \frac{4+5x}{x(x+3)}

Common denominator is

x(x+3)

Your working out is not wrong but it isn't the best way. Don't expand the denominator!

(edited 7 years ago)

OP

Original post by Math12345

\frac{4}{x(x+3)}+\frac{5}{x+3} = \frac{4}{x(x+3)}+\frac{5x}{x(x+3)} = \frac{4+5x}{x(x+3)}

Common denominator is

x(x+3)

ugh im so confused

OP

Original post by Math12345

\frac{4}{x(x+3)}+\frac{5}{x+3} = \frac{4}{x(x+3)}+\frac{5x}{x(x+3)} = \frac{4+5x}{x(x+3)}

Common denominator is

x(x+3)

Your working out is not wrong but it isn't the best way. Don't expand the denominator!

Its just with other questions the video i watched said to do it that way ;/

Original post by junayd1998

ugh im so confused

For example:

\frac{4}{18} + \frac{5}{6} = \frac{4}{18} + \frac{15}{18} = \frac{19}{18}

Since the common denominator is 18.

With your question the denominators are x(x+3) and (x+3) so the lowest common denominator is x(x+3).

Original post by junayd1998

Its just with other questions the video i watched said to do it that way ;/

The question helped you by giving the denominator factorised. You don't need to expand it.

Steps:
1. Find (lowest) common denominator.
2. Cross multiply and expand at the numerator.
3. Combine.

For example:

\frac{2}{x+1}+\frac{1}{x+2} = \frac{2(x+2)}{(x+1)(x+2)} + \frac{x+1}{(x+1)(x+2)} = \frac{3x+5}{(x+1)(x+2)}

(where the lowest common denominator is (x+1)(x+2))

(edited 7 years ago)

Try:

Unparseable latex formula:

\frac{4x}{(x+2)(x+1)} + \frac{5}{(x+2)}}

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