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
.
Since she spends 30 minutes/day walking, the total number of minutes can be represented by 30 minutes for each day or 30*amount of days=30*d
Answer:
x + -2
Step-by-step explanation:
(editing answer to add how i got it)
3x +6=-3 (2x +4)
-3 (2x +4)
Multiply using the distributive property.
−
6
x
−
12 /2
3(2)(-3x - 4)
divide these by 2 will get you
SO ITS 3(2) +6 = 3(2) (2x +4)
Answer:
43% of the students prefer biology
Step-by-step explanation:
Among girls:
39 of the students are girls.
21 of the girls like biology best.
Boys:
100 - 39 = 61 are boys.
16 prefer physics
11 out of the 34 who prefer chemistry are girls, so 34 - 11 = 23 are boys.
61 - (16 + 23) = 22 prefer biology.
What percentage of the students prefer biology?
21 boys and 22 boys, that is, 43 students out of 100. So
43*100%/100 = 43%
43% of the students prefer biology
Step-by-step explanation:
∠W and ∠Z are supplementary