How do you use cross products to solve 3/4=x/(x+3)?
3 Answers
Explanation:
or
or
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x = 9
Explanation:
To use cross products or
color(blue)"cross multiplication" as it is also named.
color(red)(3)/color(blue)(4)=color(blue)(x)/color(red)(x+3) now multiply the terms in
color(blue)("blue")" and "color(red)("red") (X) and equate them.
rArrcolor(blue)(4x)=color(red)(3(x+3)) distribute the bracket : 4x = 3x + 9
subtract 3x from both sides to solve for x
4x-3x=cancel(3x)+9cancel(-3x)rArrx=9
This is why the cross product works!!!
Explanation:
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