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Vanyuwa [196]
3 years ago
10

When you reverse the digits in a certain 2 digit number you decrease its value by 81. What is the number if the sum of its digit

s is 9?​
Mathematics
1 answer:
arlik [135]3 years ago
6 0

Answer: 90 is a number which has 9 as the sum of its digits, 9+0=9 and if the digits are reversed, 09 is 81 less than 90.

Step-by-step explanation: Since the number must be a 2-digit number, it seems that 90 is the only number that qualifies.

If you need some equations, here is a way to set up a system to solve:

x+y= 9 rewrite to get a value for y to substitute:

y = 9-x

10x +y = 10y + x + 81 rewrite by moving (subtracting variable terms from both sides)

10x -x + y-10y = 81 combine like terms

9x - 9y = 81

Substitute for y and solve for x

9x - 9(9-x)= 81 distribute.

9x - 81 + 9x = 81

18x = 162. 162/18 = 9

x = 9

Substitute in the original equation to solve for y

9 + y = 9

y = 0

10(9) + 0 = 10(0) + 9 +81

90 - 81 = 09

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Answer:

Extremely large and small numbers that have many zeros are long to write and take up a lot of room. So, by using scientific notation a number can be written shorter. For example, numbers such as 295,000,000,000 can be shortened to 2.95x10^{11}. This is easier to write and understand. This is why the scientific notation is used over standard.

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3 years ago
What is the slope of a line that is parallel to the given equation?<br> y -- 2 = 5 (x + 1)
Nezavi [6.7K]

Answer: Slope = 10.000/2.000 = 5.000

x-intercept = 7/-5 = -1.40000

y-intercept = 7/1 = 7.00000

Step-by-step explanation:

Rearrange the equation by subtracting what is to the right of the equal sign from both sides of the equation :

y-2-(5*(x+1))=0

STEP

1

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Equation at the end of step 1

(y - 2) - 5 • (x + 1) = 0

STEP

2

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Equation at the end of step 2

y - 5x - 7 = 0

STEP

3

:

Equation of a Straight Line

3.1 Solve y-5x-7 = 0

Tiger recognizes that we have here an equation of a straight line. Such an equation is usually written y=mx+b ("y=mx+c" in the UK).

"y=mx+b" is the formula of a straight line drawn on Cartesian coordinate system in which "y" is the vertical axis and "x" the horizontal axis.

In this formula :

y tells us how far up the line goes

x tells us how far along

m is the Slope or Gradient i.e. how steep the line is

b is the Y-intercept i.e. where the line crosses the Y axis

The X and Y intercepts and the Slope are called the line properties. We shall now graph the line y-5x-7 = 0 and calculate its properties

Graph of a Straight Line :

Calculate the Y-Intercept :

Notice that when x = 0 the value of y is 7/1 so this line "cuts" the y axis at y= 7.00000

y-intercept = 7/1 = 7.00000

Calculate the X-Intercept :

When y = 0 the value of x is 7/-5 Our line therefore "cuts" the x axis at x=-1.40000

x-intercept = 7/-5 = -1.40000

Calculate the Slope :

Slope is defined as the change in y divided by the change in x. We note that for x=0, the value of y is 7.000 and for x=2.000, the value of y is 17.000. So, for a change of 2.000 in x (The change in x is sometimes referred to as "RUN") we get a change of 17.000 - 7.000 = 10.000 in y. (The change in y is sometimes referred to as "RISE" and the Slope is m = RISE / RUN)

Slope = 10.000/2.000 = 5.000

Geometric figure: Straight Line

Slope = 10.000/2.000 = 5.000

x-intercept = 7/-5 = -1.40000

y-intercept = 7/1 = 7.00000

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Step-by-step explanation:

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Answer:

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Step-by-step explanation:

Hey there! I'm happy to help!

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We subtract this from 300 to see how much is left.

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Rhonda had $47.33 left after her purchases.

Have a wonderful day! :D

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