What is the ratio of x to y? 3/2 = 2x/2x+y A. -3/2 B. -2/3 C. 2/3 D. 3/2 If you're confused of what the equation is, let me know and I'll take a screenshot of the question so it's easier. But, I'm thinking it's C.
is it \[ \frac{3}{2} = \frac{2x}{2x+y} \]?
@phi Yes it is.
if you cross multiply, what do you get ?
x = 3y/2 y= 2x/3
try this multiply both sides of \[ \frac{3}{2} = \frac{2x}{2x+y} \] by 2(2x+y)
So like this? 3 * 2x + y = 2 * 2x
almost, you need parens 3*(2x+y)= 4x now distribute the 3
What do you mean distribute the 3?
3*(2x+y) means 3 times each term inside the parens
Sorry, I'm a bit confused but I got this when I times 3 by the terms in the parentheses. y = 2x -3
3*(2x+y)= 4x do 3*2x and 3*y
think of (2x+y) as a "package" and you have 3 packages (so you have 3 of everything inside the package)
But how can I multiply it if I don't know what the variables are?
you multiply letters by just showing them being multiplied example: x times y is x*y or xy obviously we don't know what number that is, but we do know that it means x times y
3*(2x+y)= 4x now distribute the 3 (i.e. multiply each term inside by 3)
So 3 x (2xy) ?
if it helps say you had 3 farms, each had 2 cows and 1 horse how many cows and horses do you have?
9?
how many of each type ?
6 cows and 3 horses.
yes you did 3( 2 cows + 1horse) and got 3*2 cows + 3*1 horse
if we count x's and y's 3(2x + 1y) = 3*2 x + 3*1 y or 6x+3y
see if you make sense of that. meanwhile 3*(2x+y)= 4x 6x+3y= 4x now add -4x to both sides 6x-4x + 3y = 4x - 4x on the right side, you have 4x take away 4 x's on the left you have 6 x's take away 4 x's (or cows if you like) that gives you 2x+3y= 0
So what do I do from here since I now have 0?
we want the ratio of x to y or x/y so divide both sides by y \[ \frac{2x+3y}{y}= \frac{0}{y} \\ \frac{2x}{y} + 3\frac{y}{y}= 0 \]
y/y is 1 so we have \[ 2 \frac{x}{y}+3=0 \] add -3 to both sides to get \[ 2 \frac{x}{y}=-3\] now divide both sides by 2
we could also do this 2x+3y= 0 3y= -2x (add -2x both sides) now divide both sides by y 3 = -2 (x/y) now divide both sides by -2 (3/-2) = x/y or x/y = -3/2
So the answer is A?
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