A. Multiplication Property of Equality

Find a_1 and d for an arithmetic sequence with these terms. a_4=9and a_7=18

jonny [76]

$\bf \begin{array}{llll}
term&value\\
-----&-----\\
a_4&9\\
a_5&9+d\\
a_6&(9+d)+d\\
&9+2d\\
a_7&(9+2d)+d\\
&9+3d=\underline{18}
\end{array}\\\\
-------------------------------\\\\
9+3d=18\implies 3d=9\implies d=\cfrac{9}{3}\implies \boxed{d=3}$

$\bf n^{th}\textit{ term of an arithmetic sequence}\\\\
a_n=a_1+(n-1)d\qquad 
\begin{cases}
n=n^{th}\ term\\
a_1=\textit{first term's value}\\
d=\textit{common difference}\\
----------\\
n=7\\
d=3
\end{cases}
\\\\\\
a_7=a_1+(7-1)d\implies 18=a_1+(7-1)3\implies 18=a_1+18
\\\\\\
18-18=a_1\implies \boxed{0=a_1}$

3 0

3 years ago

which of the following sets could be the sides of a right triangle? {2,3, square root 13} {5,5,2 square root 10} {5,12,15}

anastassius [24]

All of these sets meet the requirements of the triangle inequality. The sum of any two numbers in the set is greater than the third one. (You really only need to check that the sum of the smallest two is greater than the largest.)

It can help to resolve the numbers that are only indicated as to value.

√13 ≈ 3.606

2√10 ≈ 6.325

_____

Your comparisons can be ...

2 + 3 = 5 > 3.606 . . . is a triangle

5 + 5 = 10 > 6.325 . . . . . . is a triangle

5 + 12 = 17 > 15 . . . . . . . . is a triangle

8 0

3 years ago

How do you solve -50x3/1000

Finger [1]

Answer:

-.15

Step-by-step explanation:

3/1000= .003

-50×.003= -.15

7 0

3 years ago

Dog's video shop rent games for 3 games for $9.99. What is

forsale [732]

Answer:$43.29

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Choose 5 cards from a full deck of 52 cards with 13values (2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A) and 4 kinds(spade, diamond, h

Delvig [45]

Answer:

a) 182 possible ways.

b) 5148 possible ways.

c) 1378 possible ways.

d) 2899 possible ways.

Step-by-step explanation:

The order in which the cards are chosen is not important, which means that we use the combinations formula to solve this question.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

In this question, we have that:

There are 52 total cards, of which:

13 are spades.

13 are diamonds.

13 are hearts.

13 are clubs.

(a)Two-pairs: Two pairs plus another card of a different value, for example:

2 pairs of 2 from sets os 13.

1 other card, from a set of 26(whichever two cards were not chosen above). So

$T = 2C_{13,2} + C_{26,1} = 2*\frac{13!}{2!11!} + \frac{26!}{1!25!} = 182$

So 182 possible ways.

(b)Flush: five cards of the same suit but different values, for example:

4 combinations of 5 from a set of 13(can be all spades, all diamonds, and hearts or all clubs). So

$T = 4*C_{13,5} = 4*\frac{13!}{5!8!} = 5148$

So 5148 possible ways.

(c)Full house: A three of a kind and a pair, for example:

4 combinations of 3 from a set of 13(three of a kind ,c an be all possible kinds).

3 combinations of 2 from a set of 13(the pair, cant be the kind chosen for the trio, so 3 combinations). So

$T = 4*C_{13,3} + 3*C_{13.2} = 4*\frac{13!}{3!10!} + 3*\frac{13!}{2!11!} = 1378$

So 1378 possible ways.

(d)Four of a kind: Four cards of the same value, for example:

4 combinations of 4 from a set of 13(four of a kind, can be all spades, all diamonds, and hearts or all clubs).

1 from the remaining 39(do not involve the kind chosen above). So

$T = 4*C_{13,4} + C_{39,1} = 4*\frac{13!}{4!9!} + \frac{39!}{1!38!} = 2899$

So 2899 possible ways.

4 0

3 years ago