Answer:
r = -1/2
Step-by-step explanation:
3(5 + 4r) = -18r
15 +12r = -18r by distributive property
15 = -12r - 18r
15 = -30r
r = - 1/2r
Answer:
The correct number of basic operations that exist in mathematics is four (addition, subtraction, multiplication and division) because the definition of an operation is the carrying out of a task by the application of principles and these four operation are arithmetic operations that have precedence rules or order of operations, such that we must first multiply or divide before adding or subtracting
Division is different from simply multiplying by a fraction because in Euclidean division, the result is a quotient and a remainder, which shows that division can yield more than one result while multiplication yields a single result
For subtraction and addition, one of the differences is that subtraction cannot be simply commuted
a - b = -(b - a)
Subtraction is non-associative;
a - b - c when arranged as (a - b) - c and a - (b - c), can yield different results depending on operation order which is unlike addition
Therefore, the four basic operations in mathematics are addition, subtraction, multiplication and division
Step-by-step explanation:
Here's number 5. If you need more explanation just let me know.
Answer:
<em>After </em><em>47</em><em> days she will have more than 90 trillion pennies.</em>
Step-by-step explanation:
At the beginning there was 1 penny. At the second day the amount of pennies under the pillow became 2.
The amount of pennies doubled each day. So the series is,

This series is in geometric progression.
As the pennies from each of the previous days are not being stored away until more pennies magically appear so the sum of series will be,

where,
a = initial term = 1,
r = common ratio = 2,
As we have find the number of days that would elapse before she has a total of more than 90 trillion, so









Answer:
b & c for sure
Step-by-step explanation:
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