Answer:
Step-by-step explanation:
To write fractions with a common denominator, you will most likely need to scale some numbers up! I will explain how.
Let's try it with the fractions
2
3
and
3
12
12 is larger than 3, so we will have to multiply the 3 by some number to equal 12. (We are really finding the Least Common Multiple of the two denominators!) To do this, you have to multiply the 3 by 4, because 3x4=12. But now the numerator doesn't match the denominator. When you scale the denominator up, you have to scale the numerator up too! So the 2 must be multiplied by 4 also.
Now you have the following:
8
12
and
3
12
These fractions now have common denominators! Now they're all set for adding or subtracting fractions.
Try another:
2
6
and
3
5
: The least common multiple of 6 and 5 is 30. (the product of the denominators)
Transform each fraction by multiplying by "1":
2
6
⋅
5
5
=
10
30
and
3
5
⋅
6
6
=
18
30
One last problem:
4
9
and
7
6
What is the least common multiple of 9 and 6? Could you use 54? Absolutely, but it is not the LEAST number that you could use. How about 18? YES!
4
9
⋅
2
2
=
8
18
and
7
6
⋅
3
3
=
21
18
Ready to go...
Hope this helped!
1.5,1.25,1.75,3.5 for number 3
Scores are {72, 97, 82, x} where x is the unknown fourth score
They add up to 72+97+82+x = x+251
Divide this sum over four because there are four scores we want to average out. We end up with (x+251)/4 = M where M is the mean. Asa wants the mean to be 82, so make M = 82.
We can replace M with 82 and solve for x like so
(x+251)/4 = M
(x+251)/4 = 82
x+251 = 4*82
x+251 = 328
x = 328-251
x = 77
Asa needs a score of 77 on the fourth test so that the mean of the four tests is 82. If she scores higher than 77 on the fourth test, then the mean will be larger than 82.
-----------------------------------
Depending on what your teacher is looking for, the first step is to establish your variable. So you would say "let x = fourth score". However, that seems too easy. So perhaps your teacher is looking for the equation (x+251)/4 = 82 or some variant of it.
Answer:
131.1 in^2
Step-by-step explanation:
a=πr^2
(x^4 - 9)(x^3 + 9)
This is a binomial * binomial. Use the FOIL method for multiplying.
First, outer, inner, last.
x^4 * x^3 = x^7
x°^4 * 9 = 9x^4
-9 * x^3 = -9 x^3
-9 * 9 = -81
Putting it back together.
x^7 +9x^4 -9x^3 - 81
