Mathematics, 14.07.2019 07:00 tray71016

What is the sum of the geometric sequence -4, 24, -144, if there are 7 terms? a: -159,964 b: -26,661 c: 26,661 d: 159,963

Answers: 1

Show answers

Answers

Answer from: thechef129

$a_1=-4;\ a_2=24;\ a_3=-144;\ ...\\\\r=\dfrac{a_2}{a_1}\\\\r=\dfrac{24}{-4}=-6$

The formula of the sum of a geometric sequence:

$S_n=\dfrac{a_1(1-r^n)}{1-r}$

We have:

$a_1=-4;\ r=-6;\ n=7$

substitute:

$S_7=\dfrac{-4(1-(-6)^7)}{1-(-6)}=\dfrac{-4(1-(-279,936))}{1+6}=\dfrac{-4(1+279,936)}{7}\\\\=\dfrac{-4\cdot279,937}{7}=-159,964$

A: -159,964

Answer from: Quest

all it means is function 3

Answer from: Quest

ratios represent a pattern or relationship that can be scaled.

equivalent ratios are pairs of ratios that represent the same relationship between quantities, and can be generated by multiplying or dividing both quantities in the ratio by the same factor.

in this lesson, students will use double number lines and ratio reasoning to solve ratio problems. by partitioning double number lines into proportionate intervals, students will build an understanding of equivalent ratio relationships as those that are generated by multiplying or dividing two related quantities by the same number. this lesson will build upon students' prior understanding of multiplicative comparisons, number line reasoning and equivalent fractions (while highlighting the difference between equivalent fractions and equivalent ratios); and will build toward future work in this unit on building ratio tables, and work in future grades in proportionality, scaling, and expressing and graphing linear functions.

step-by-step explanation:

ratios represent a pattern or relationship that can be scaled.

equivalent ratios are pairs of ratios that represent the same relationship between quantities, and can be generated by multiplying or dividing both quantities in the ratio by the same factor.

Another question on Mathematics

Mathematics, 21.06.2019 15:00

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

Answers: 1

Answer

Mathematics, 21.06.2019 22:30

If you prove that ∆wxz is congruent to ∆yzx, which general statement best describes what you have proved?

Answers: 3

Answer

Mathematics, 21.06.2019 23:20

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?

Answers: 3

Answer

Mathematics, 21.06.2019 23:30

Write an inequality for this sentence the quotient of a number and -5 increased by 4 is at most 8