2+1=3
15/3=5
split the 3 5's in ratio 2:1 and you get 10:5
You can just 1) multiply the binomial by itself, or you can use 2) the square of a binomial pattern. I'll show it to you both ways.
1) Multiply the binomial by itself.
(3x - 2)^2 = (3x - 2)(3x - 2) =
Multiply every term of the first binomial by every term of the second binomial, then collect like terms. (This is often called using FOIL.)
= 9x^2 - 6x - 6x + 4
= 9x^2 - 12x + 4
2) Use the square of a binomial pattern
The square of a binomial is
(a - b)^2 = a^2 - 2ab - b^2
a^2 is the square of the first term.
b^2 is the square of the second term.
-2ab is the product of the two terms and 2.
You have
(3x - 2)^2,
where the first term is 3x, and the second term is -2
square the first term: 9x^2
square the last term: 4
the product of the terms and 2 is: -12x
Put it all together, and you get
9x^2 - 12x + 4
just like we got above with the other method.
Answer: Option #4: the 0.2 could be changed to 2.
Explanation:
The table is designed to make the concept of percentages more understandable. The table first allocates the total amount of 70 in terms of its "fifths," or 20% parts. Then it expresses these parts in the last row of the table, showing that 20% of 70 is 14 and all the five parts sum up to 70 again.
Now, Mikel is supposed to express 40% of the amount. So she writes (incorrectly): 0.2 * 14. This statement needs to be changed to 2 * 14 (two times 14 = 28), to correspond to 2 times 20%, or 40% of 70.
This is reflected in the last (fourth) option "The 0.2 in the expression could be changed to 2."
Option #3 is incorrect because changing 14 to 70, will result in an incorrect number (2.8).
Options 1 and 2 are similarly incorrect (as can be easily verified)
The answer is D. 12
4, 3 and 2 are all factors of 12 (least common denominator)
