Question

Plz anyone help me to explain cross multiplication method??No spams plz..its my exm on 28 and i m not remembering anything...my frnds r offline nd tution teacher is on a trip...plz help me guys...I ll mark as brainlies but explain me

Answer 1

To cross multiply is to go

from this:

812 = 23

to this:

8 × 3 = 12 × 2

How Does it Work?

Multiplying the top and bottom of a fraction by the same amount doesn't change its value.

Step 1: Multiply the top and bottom of the firstfraction by the bottom number of the secondfraction.

8 × 312 × 3 = 23

Step 2: Multiply the top and bottom of thesecond fraction by the bottom number that thefirst fraction had.

8 × 312 × 3 = 2 × 123 × 12

And Magic! The bottom of both fractions is now12 × 3

Step 3: We can get rid of the 12 × 3 (as we are dividing both sides by the same amount) and the equation is still true:

8 × 3 = 12 × 2

Job Done!

In practice, though, it is easier to skip the steps and go straight to the "cross-multiplied" form.

Using Variables

The general case, using variables instead of numbers, is:

To cross multiply is to go from this:ab = cd

To this:ad = bc

 

Answer 2

Hey!!!
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●Cross multiplication refers to two equations seperated by equal sign and is in divide form like
$\frac{30}{12} = \frac{5}{2} \\ 30 \times 2 = 5 \times 12$
you can see here when cross multiplication happens division became open
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Hope it helps!!! :)