Its a common technique for remembering the order of operations. The abbreviation pemdas is turned into the phrase "Please excuse my Dear Aunt Sally". It stands for "Parentheses, Exponents, Multiplication and Division, and Addition and Subtraction.
Answer:
n=2m
Step by step:
total=rate of movie watching per month times months
n=2 movies per month times 'm' months, so,
n=2m
In 10 months Lisa will have paid the same amount as Kelly, but in month 11 she will have paid more.
Answer:
24/5
Step-by-step explanation:
5x : 9
(8 : 3)×3
5x : 9
24 : 9
5x = 24
x = 24/5 = 4/4/5
Answer:
3x^2 + 3xy/2 - 7xy^2/2
Step-by-step explanation:
So we know the perimeter is 20x^2 + xy - 7y^2,
To find any perimeter you need 2l + 2w = P so,
One of the sides is 7x^2 - xy
First plug in the values,
2(7x^2-xy) + 2w = 20x^2 + xy - 7y^2
Multiply,
14x^2-2xy + 2w = 20x^2 + xy - 7y^2
Subtract,
14x^2 - 2xy - 14x^2 + 2xy + 2w = 20x^2 + xy - 7y^2 - 14x^2 + 2xy
2w = 6x^2 + 3xy - 7y^2
w = 3x^2 + 3xy/2 - 7xy^2/2