It took Aiden 6 hours to plant 8 trees. How many hours would it take for him to plant 20 trees? 24, 18, 23, 15

Mathematics

1 answer:

Pepsi [2]2 years ago

7 0

<h3>Answer: 15 hours (choice D)</h3>

================================================

Work Shown:

(6 hours)/(8 trees) = (x hours)/(20 trees)

6/8 = x/20

6*20 = 8*x ... cross multiply

120 = 8x

8x = 120

x = 120/8

x = 15

It takes him 15 hours to plant 20 trees.

You might be interested in

PLEASE HELP I WILL GIVE BRAINLIEST

Triss [41]

Answer:

20 inches²

Step-by-step explanation:

perimeter = 8 + 3 + 5 + 4

= 20 inches²

4 0

2 years ago

Which of the following is an extraneous solution of (45-3x)^1/2=x-9?

Iteru [2.4K]

Answer:

C. x =3

Step-by-step explanation:

Extraneous solution is that root of a transformed equation that doesn't satisfy the equation in it's original form because it was excluded from the domain of the original equation.

Let's solve the equation first

$\sqrt{45-3x} = x-9\\Taking\ square\ on\ both\ sides\\{(\sqrt{45-3x})}^2 = {(x-9)}^2\\45-3x = x^2-18x+81\\0 = x^2-18x+81-45+3x\\x^2-15x+36 = 0\\x^2-12x-3x+36 = 0\\x(x-12)-3(x-12) = 0\\(x-3)(x-12)\\x-3 = 0\\=> x =3\\x-12 = 0\\x = 12\\We\ will\ check\ the\ solutions\ one\ by\ one\\So,\\for\ x=3\\\sqrt{45-3(3)} = 3-9\\\sqrt{45-9} = -6\\\sqrt{36}= -6\\6\neq -6\\For x=12\\\sqrt{45-3(12)} = 12-9\\\sqrt{45-36} = 6\\\sqrt{36}= 6\\6=6$

Hence, we can conclude that x=3 is an extraneous solution of the equation ..

3 0

3 years ago

How many real roots does a quadratic equation have if the discriminant is -3?

soldier1979 [14.2K]

$\bf \qquad \qquad \qquad \textit{discriminant of a quadratic} \\\\\\ y=\stackrel{\stackrel{a}{\downarrow }}{a}x^2\stackrel{\stackrel{b}{\downarrow }}{+b}x\stackrel{\stackrel{c}{\downarrow }}{+c} ~~~~~~~~ \stackrel{discriminant}{b^2-4ac}= \begin{cases} 0&\textit{one solution}\\ positive&\textit{two solutions}\\ negative&\stackrel{\textit{no real roots}}{\textit{no solution}}\quad \checkmark \end{cases}$