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2 years ago

1

Mathematics

1 answer:

Setler79 [48]2 years ago

6 0

Answer:

1/4 + x = (-5)/4

x = -5/4 - 1/4

x = (-5)-1 /4

x = (-6)/4

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2. Carl needs 15 hours longer than Jennifer to paint a room. If they work together, they can complete the job in 4 hours. Explai

nasty-shy [4]

Answer:

Jennifer would complete the job on her own in 5 hours.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}$

$\Delta = b^{2} - 4ac$

Rates

The together rate is the sum of their separates rate.

We have that:

Jennifer takes x hours to complete the job on her own, so her rate is 1/x.

Carl needs 15 hours longer than Jennifer, that is, 15 + x hours, so his rate is 1/(15+x).

The together rate is 1/4. So

$\frac{1}{4} = \frac{1}{x} + \frac{1}{15+x}$

$\frac{1}{4} = \frac{15 + x + x}{x(15+x)}$

$\frac{1}{4} = \frac{15 + 2x}{x(15+x)}$

Applying cross multiplication.

$x^2 + 15x = 4(15 + 2x)$

$x^2 + 15x = 60 + 8x$

$x^2 + 7x - 60 = 0$

Quadratic equation with $a = 1, b = 7, c = -60$ . So

$\Delta = 7^{2} - 4*1*60 = 289$

$x_{1} = \frac{-7 + \sqrt{289}}{2} = 5$

$x_{2} = \frac{-7 - \sqrt{289}}{2} = -12$

Since the time to complete the job has to be a positive value.

Jennifer would complete the job on her own in 5 hours.

4 0

2 years ago

What’s the cube root of -9

Aneli [31]

It might be -3 because 3•-3 is -9?

7 0

3 years ago

In Spencer’s garden, the number of rose bushes is 7 less than 1.5 times the number of carnation bushes. If the number of carnati

adelina 88 [10]

If carnation bushes is c, then the expression representing the number of rose bushes would be...

1.5c - 7

5 0

3 years ago

Read 2 more answers

Verify if f(x)= 5-3x/2 and g(x)= 5-2x/3 are inverses. Please show step by step.

mestny [16]

Since f(g(x)) = g(f(x)) = x, hence the function f(x) and g(x) are inverses of each other.

<h3>Inverse of functions</h3>

In order to determine if the function f(x) and g(x) are inverses of each other, the composite function f(g(x)) = g(f(x))

Given the function

f(x)= 5-3x/2 and

g(x)= 5-2x/3

f(g(x)) = f(5-2x/3)

Substitute

f(g(x)) = 5-3(5-2x)/3)/2

f(g(x)) = (5-5+2x)/2

f(g(x)) = 2x/2

f(g(x)) = x

Similarly

g(f(x)) = 5-2(5-3x/2)/3

g(f(x)) = 5-5+3x/3

g(f(x)) = 3x/3

g(f(x)) =x

Since f(g(x)) = g(f(x)) = x, hence the function f(x) and g(x) are inverses of each other.

Learn more on inverse of a function here: brainly.com/question/19859934

#SPJ1

7 0

1 year ago

Millie has a box of 1 hundred cubes. She also has a bag of 70 cubes. How many trains of 10 cubes can she make?

ANTONII [103]

She has a total of 170 cubes

170/10=17 trains

7 0

3 years ago

Read 2 more answers