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3 years ago

Solve the linear equation: x-y=7 0.5x+y=5

Mathematics

1 answer:

evablogger [386]3 years ago

4 0

Add the equations.

x-y%2B0.5x%2By=7%2B5

1.5x=12

highlight%28x=8%29

Now use either equation to solve for y.

8-y=7

highlight%28y=1%29

x=8

y=1

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there are nickels, dimes, and quarters in a piggy bank. altogether, the coins are worth $3.65. the number of dimes is three time

hoa [83]

This question is solved using a system of equations, and doing this, we get that: There are 9 quarters, 4 nickels and 12 dimes.

I am going to say that:

x is the number of nickels.

y is the number of dimes.

z is the number of quarters.

In all, they are worth $3.65.

A nickel is worth $0.05, a dime is worth $0.1 and a quarter is worth $0.25, so:

$0.05x + 0.1y + 0.25z = 3.65$

Dimes: 3 times greater than nickels:

This means that:

$y = 3x$

Quarters: One greater than double the number of nickels:

This means that:

$z = 2x + 1$

Value of x:

We have y and z as function of x, so we can replace into the equation and find the value of x, so:

$0.05x + 0.1y + 0.25z = 3.65$

$0.05x + 0.1(3x) + 0.25(2x+1) = 3.65$

$0.05x + 0.3x + 0.5x + 0.25 = 3.65$

$0.85x = 3.4$

$x = \frac{3.4}{0.85}$

$x = 4$

y and z:

$y = 3x = 3(4) = 12$

$z = 2x + 1 = 2(4) + 1 = 9$

There are 9 quarters, 4 nickels and 12 dimes.

A similar question is found at brainly.com/question/17096268

4 0

3 years ago

The low temperatures for 5 days was 5, -2, -11 ,0 and-3.What was the average low temperature for those days

Daniel [21]

Data:
Average (A): ?
Arithmetic mean (A.M) = 5, -2, -11, 0, -3sum of n numbers = 5

Solving:
$A = \frac{AM}{n} = \frac{5+(-2)+(-11)+0+(-3)}{5} = \frac{5-2-11-3}{5} = \frac{\diagup\!\!\!\!3-11-\diagup\!\!\!\!3}{5} = \frac{-11}{5} = - 2.2$

Answer:

The average low temperature of these days is -2.2

3 0

3 years ago

Evaluate the difference quotient for the given function. Simplify your answer.

nasty-shy [4]

I suppose you mean

$f(x) = \dfrac{x+5}{x+1}$

Then

$f(3) = \dfrac{3+5}{3+1} = \dfrac84 = 2$

and the difference quotient is

$\dfrac{f(x)-f(3)}{x-3} = \dfrac{\frac{x+5}{x+1}-2}{x-3} \\\\ \dfrac{f(x)-f(3)}{x-3} = \dfrac{\frac{x+5-2(x+1)}{x+1}}{x-3} \\\\ \dfrac{f(x)-f(3)}{x-3} = \dfrac{-x+3}{(x+1)(x-3)} \\\\ \dfrac{f(x)-f(3)}{x-3} = \boxed{-\dfrac{x-3}{(x+1)(x-3)}}$

If it's the case that x ≠ 3, then (x - 3)/(x - 3) reduces to 1, and you would be left with

$\dfrac{f(x)-f(3)}{x-3}\bigg|_{x\neq3} = -\dfrac1{x+1}$

4 0

2 years ago

Pre college need help with

kati45 [8]

Answer:

check online for more information

8 0

2 years ago

What is the sign of 3x y3xy3, x, y when x>0x>0x, is greater than, 0 and y<0y<0y, is less than, 0?

kaheart [24]

Answer:

B ) Negative

Step-by-step explanation:

Given the expression 3xy

when x>0 and y<0

The value of the expression 3xy will be negative.

This is because the product of a positive and negative number will always be negative.

For illustration,

Let x=5>0 and y=-5<0

3xy=3(5)(-5)=-75

NOTE:

$-X-=+\\-X+=-\\+X+=+$

5 0

3 years ago