How do you use cross products to solve #3/4=x/(x+3)#?
x = 9
To use cross products or
#color(blue)"cross multiplication"#as it is also named.
now multiply the terms in
#color(blue)("blue")" and "color(red)("red")#(X) and equate them.
distribute the bracket : 4x = 3x + 9
subtract 3x from both sides to solve for x
This is why the cross product works!!!
The cross product is a shortcut that bypasses some stages in solving by first principles. I will use first principles so you can see where the shortcut takes over.
A fraction is split up into two parts. Using descriptive but
When you wish to
Using a 'common denominator' of
If you look at the numerators you will see the result you get by the short cut
Multiply both sides by