what does cross multiplication mean?

Answer 1

If you have (w+x)(y+z) cross multiply means multiple each term on the left with each term on the right and add them.
(w+x)(y+z)=wy+wz+xy+xz

Answer 2

Cross multiplictation is a short cut that I will explain, that only confuses people.
suppose you have an equation such as
2/x=5/3
Cross multiplication is when you multiply the left side of the equation by the denominator of the right side and visa versa..
or 3*2 = 5 x

The real mathematical principle behind the process is to multiply both sides by the denominators - multiply both sides by 3, and then rby x
3*2/x = 5
3*2 = 5x
Why do I say it's confusing? when there are multiple terms on either side - cross multiplying then gets confusing.
That's why I always suggest that one not learn cross multiplicaiton, but instead learn to multiply both sides of the equation by the same value - then it always work - even if there are multiple terms.
2x + 5/2 = 7 - 2/x
as you can see, cross multiplying wouldn't work easily in this case.

Answer 3

Cross multiplication is when you multiply the numerator by the denominator of the other fraction . For example:


3 x You multiply 3 x 16 and 4 * x
-- = ---- and you come up with 4x=48 x=12
4 16

Answer 4

It can mean a couple of different things. In algebra, it means that if you have a/b = c/d, that this is equal to ad = bc. It's called "cross multiplying" because if you write out the equation with fractions and draw a line connecting a with d, and b with c, you get two diagonal lines crossing over each other. This is helpful if you want to solve an equation like 3/x = 7/9.

Answer 5

If you want the basic concept, you are just multiplying the numerator by teh denominator of the SECOND fraction. For example. Let say you have:

2/4 = 3/6

Then you multiply 2*6 OR 3*4. That is cross multiply. If you picture it, you are multiplying diagnally or "crossing" as the name suggested.

Hope this is helpful and have fun!

Answer 6

let's say you want to solve the following:
(1/2)+ (3/5) = ?
cross multiply to get the common denominator:
[(1)(5)+ (3)(2)]/(2)(5)=
(5+6)/10 = 11/10

Answer 7

Multiply the factors that are across
Divide then with a number with the letter N
N= none

Answer 8

It is a rule that says that when you have two fractions that are equal to each other such that a/b=z/x, ax=bz. This can be useful when one of the values is unknown or for extrapolating numbers from past observations form proportions

Answer 9

it means to multiply diagonally

Answer 10

the ans wrong and you've fail the test .. get up leave the class now !!!