Answer:
y = 3 - 2x
Step-by-step explanation:
The goal is to isolate the y variable
In order to have y by itself (on one side of the equation or equal sign), we must move the other numbers and variables to the other side.
Since 2x is on the same side as y, we have to subtract it from both sides. Subtracting it cancels out the original 2x and leaves the equation to look like this:
y = 3 - 2x
Now the y is isolated
Another example:
-5x + y = 15
To isolate the y, we must cancel out the -5x. Add 5x to both sides. It will cancel out the -5x and bring it to the right side of the equation, resulting in:
y = 15 + 5x
Answer:
Step-by-step explanation:
Both expressions are examples of the <em>distributive property</em>, which basically says "if I have <em>this </em>many groups of some size and <em>that</em> many groups of the same size, I've got <em>this </em>+ <em>that</em> groups of that size altogether."
To give an example, if I've got <em>3 groups of 5 </em>and <em>2 groups of 5</em>, I've got 3 + 2 = <em>5 groups of 5 </em>in total. I've attached a visual from Math with Bad Drawings to illustrate this idea.
Mathematically, we'd capture that last example with the equation
. We can also read that in reverse: 3 + 2 groups of 5 is the same as adding together 3 groups of 5 and 2 groups of 5; both directions get us 8 groups of 5. We can use this fact to rewrite the first expression like this: 
.
This idea extends to subtraction too: If we have 3 groups of 4 and we take away 1 group of 4, we'd expect to be left with 3 - 1 = 2 groups of 4, or in symbols: 
. When we start with two numbers like 15 and 10, our first question should be if we can split them up into groups of the same size. Obviously, you could make 15 groups of 1 and 10 groups of 1, but 15 is also the same as <em>3 groups of 5</em> and 10 is the same as <em>2 groups of 5</em>. Using the distributive property, we could write this as 
, so we can say that 
.
24x^3-40x^2. 45x-75
8x^2(3x-5). 15(3x-5)
(8x^2+15)(3x-5)
I believe the answer would be 9.
