Question

(1/4 + 1/3 = 1/x)

Answer 1

\( \color{Black}{\Rightarrow \large {1 \over 4} + {1 \over 3} = {1 \over x} }\)

\( \color{Black}{\Rightarrow \large {3 \over 12} + {4 \over 12} = {1 \over x} }\)

Does this help you?

Answer 2

7/12?

Answer 3

yeah, now cross multiply.

Answer 4

cross multiply what?

Answer 5

\( \color{Black}{\Rightarrow \Large {a \over b} = {x \over y} \Longrightarrow ax = by }\)

Answer 6

so 7/12 x 1/x = 7x/12?

Answer 7

7x = 12

Answer 8

you have
\[ \frac{7}{12}= \frac{1}{x} \]
to find x you could do a few things.
1) flip both fractions
2) multiply both fractions by 12x to get 7x=12, then divide both sides by 7
3) cross multiply to get 7x= 12, then divide both sides by 7
4) re-write the left side as
\[ \frac{1}{\frac{12}{7}} \]
and match x with the bottom:
\[ \frac{1}{\frac{12}{7}} = \frac{1}{x}\]

Answer 9

Thanks guys