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2 years ago

11

Deisha saved d dollars last month. This month she saved $8 more than 3 times the amount she saved last month. She saved a total

of $141

1 answer:

DaniilM [7]2 years ago

3 0

Answer:

Step-by-step explanation:

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Find the product of all real values of r for which 1/2x=r-x/7

Dahasolnce [82]

Answer:

$r = \±\sqrt{14$

$Product = -14$

Step-by-step explanation:

Given

$\frac{1}{2x} = \frac{r - x}{7}$

Required

Find all product of real values that satisfy the equation

$\frac{1}{2x} = \frac{r - x}{7}$

Cross multiply:

$2x(r - x) = 7 * 1$

$2xr - 2x^2 = 7$

Subtract 7 from both sides

$2xr - 2x^2 -7= 7 -7$

$2xr - 2x^2 -7= 0$

Reorder

$- 2x^2+ 2xr -7= 0$

Multiply through by -1

$2x^2 - 2xr +7= 0$

The above represents a quadratic equation and as such could take either of the following conditions.

(1) No real roots:

This possibility does not apply in this case as such, would not be considered.

(2) One real root

This is true if

$b^2 - 4ac = 0$

For a quadratic equation

$ax^2 + bx + c = 0$

By comparison with $2x^2 - 2xr +7= 0$

$a = 2$

$b = -2r$

$c =7$

Substitute these values in $b^2 - 4ac = 0$

$(-2r)^2 - 4 * 2 * 7 = 0$

$4r^2 - 56 = 0$

Add 56 to both sides

$4r^2 - 56 + 56= 0 + 56$

$4r^2 = 56$

Divide through by 4

$r^2 = 14$

Take square roots

$\sqrt{r^2} = \±\sqrt{14$

$r = \±\sqrt{14$

Hence, the possible values of r are:

$\sqrt{14$ or $-\sqrt{14$

and the product is:

$Product = \sqrt{14} * -\sqrt{14}$

$Product = -14$

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3 years ago

Between what two numbers is the exact product of 379 and 8

ANEK [815]

"Product" means to multiply, so you have to multiply 379 by 8 to get 3,032; it's between the numbers 3,031 and 3,033

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3 years ago

An equation is shown.

Anit [1.1K]

We take the equation 4x+y=5 and subtract 4x from both sides to get
y = 5 - 4x
The answer to this question is <span>y=5−4x.</span>

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3 years ago

Jesse wants to paint the top of the table shown. What is the approximate area that she will paint? Circumference is 78 inches.

Salsk061 [2.6K]

Answer:

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Step-by-step explanation:

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