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4 years ago

How do u add and subtract decimals ?

Mathematics

2 answers:

Nikolay [14]4 years ago

7 0

Write down the numbers, one under the other, with the decimal points lined up. Put in zeros so the numbers have the same length, Then add using column addition, remembering to put the decimal point in the answer. Do the same for subtracting.

Anarel [89]4 years ago

5 0

<h2>line up your decimals its like normal math but its decimals just make sure to line them up :)) (O-03)</h2><h2> </h2>

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Write 9/12 as a sum of unit fractions

Svetlanka [38]

9/12=1/2+1/4 hope this helps

5 0

4 years ago

Learning Task 3:

padilas [110]

Answer:

$Area = x^2- 25$

$Area =9x^2 +24x + 16$

$Length = (3x -2)$

$Speed = \left(y^2-3y+1\right)$

$Product = 3m^3 + 6m^2 - 6m$

Step-by-step explanation:

Solving (1):

$Length = (x + 5)$

$Width = (x - 5)$

Required

Calculate Area

$Area = Length * Width$

$Area = (x + 5) * (x - 5)$

$Area = x^2 + 5x - 5x - 25$

$Area = x^2- 25$

Solving (2):

Given

$Length = (3x + 4)$

Required: Calculate Area

$Area =Length * Length$

$Area =(3x + 4) * (3x + 4)$

$Area =9x^2 + 12x + 12x + 16$

$Area =9x^2 +24x + 16$

Solving (3):

$Area = 3x^2 + 7x - 6$

$Width = x + 3$

Required: Calculate Length

$Area = Length * Width$

$Length = \frac{Area}{Width}$

$Length = \frac{3x^2 + 7x - 6}{x + 3}$

Factorize the numerator

$Length = \frac{3x^2 + 9x -2x - 6}{x + 3}$

$Length = \frac{3x(x + 3) -2(x + 3)}{x + 3}$

$Length = \frac{(3x -2) (x + 3)}{x + 3}$

Divide by x + 3

$Length = (3x -2)$

Solving (4):

$Distance = (2y^3 - 7y^2 + 5y -1)$

$Time = 2y - 1$

Required: Determine the average speed

This is calculated as:

$Speed = \frac{Distance}{Time}$

$Speed = \frac{2y^3 - 7y^2 + 5y -1}{2y - 1}$

Factorize the numerator

$Speed = \frac{\left(2y-1\right)\left(y^2-3y+1\right)}{2y - 1}$

$Speed = \left(y^2-3y+1\right)$

Solving (5):

Multiply $(m^2 + 2m - 2)$ by sum of $(m + 3)$ and $(2m - 3)$

First, calculate the sum:

$Sum = m + 3 + 2m - 3$

$Sum = m + 2m+3 - 3$

$Sum = 3m$

Then, the product

$Product = (m^2 + 2m - 2)(3m)$

$Product = 3m^3 + 6m^2 - 6m$

6 0

3 years ago

Read 2 more answers

Quick Start Company makes 12-volt car batteries. After many years of product testing, the company knows that the average life of

Oduvanchick [21]

Answer:

a) The company should expect to replace 11.51% of its batteries.

b) 35 months.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 43.8, \sigma = 6.5$

(a) If Quick Start guarantees a full refund on any battery that fails within the 36-month period after purchase, what percentage of its batteries will the company expect to replace?

This is the pvalue of Z when X = 36. Then

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{36 - 43.8}{6.5}$

$Z = -1.2$

$Z = -1.2$ has a pvalue of 0.1151.

The company should expect to replace 11.51% of its batteries.

(b) If quick Start does not want to make refunds for more than 10% of its batteries under the full refund guarantee policy, for how long should the company guarantee the batteries (to the nearest month)?

The warranty should be the 10th percentile, which is X when Z has a pvalue of 0.1. So it is X when Z = -1.28.

$Z = \frac{X - \mu}{\sigma}$

$-1.28 = \frac{X - 43.8}{6.5}$