6 times what equals 27

What values of x make the equation x^2 - 18x + 81 = 0 true?

serg [7]

Answer: X=9

x^2 −2(x) (9)+9^2 =0

(X-9)^2=0

X-9=0

X=9

3 0

2 years ago

It takes 32 hours for a motorboat moving downriver to get from pier A to pier B. The return journey takes 48 hours. How long doe

lina2011 [118]

Answer:

Time taken by the un powered raft to cover this distance is T = 192.12 hr

Step-by-step explanation:

Let speed of boat = u $\frac{km}{hr}$

Speed of current = v $\frac{km}{hr}$

Let distance between A & B = 100 km

Time taken in downstream = 32 hours

$32 = \frac{100}{u +v}$

$u + v = \frac{100}{32}$

u + v = 3.125 ------ (1)

Time taken in upstream = 48 hours

$48 = \frac{100}{u -v}$

$u -v = \frac{100}{48}$

u - v = 2.084 ------- (2)

By solving equation (1) & (2)

u = 2.6045 $\frac{km}{hr}$

v = 0.5205 $\frac{km}{hr}$

Now the time taken by the un powered raft to cover this distance

$T = \frac{100}{v}$

Because un powered raft travel with the speed of the current.

$T = \frac{100}{0.5205}$

T = 192.12 hr

Therefore the time taken by the un powered raft to cover this distance is

T = 192.12 hr

3 0

3 years ago

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A holiday toy drive is putting together baskets for children they’re 84 toys and 56 books if each basket or see the same number

BaLLatris [955]

Answer:

28

Step-by-step explanation

we can use Greatest common divisor to solve

84 and 56 Greatest common divisor is 28(you can try)

so is 28 basket and every basket has 3 toys and 2 books

3 0

3 years ago

Which set is closed under subtractionWhich answer choice shows that the set of irrational numbers is not closed under addition

vovikov84 [41]

Answer:

(a) Set of rational numbers

(b) $\pi + (-\pi) = 0$

Step-by-step explanation:

Solving (a): Set that is closed under subtraction

The solution to this is rational numbers.

For a set of number to be closed under subtraction, the following condition must be true

$a -b = c$

Where

a, b, c are of the same set.

The above is only true for rational numbers.

e.g.

$1 - 2 = -1$

$5 - 5 = 0$

$\frac{1}{2} - \frac{1}{4} = \frac{1}{2}$

$4 - 2 = 2$

The operations and the result in the above samples are rational numbers.

Solving (b): Choice not close under addition[See attachment for options]

As stated in (a)

For a set of number to be closed under subtraction, the following condition must be true

$a -b = c$

Where

a, b, c are of the same set.

In the given options (a) to (d), only

$\pi + (-\pi) = 0$ is not close under addition because:

$\pi$ is irrational while $0$ is rational

<em>In other words, they belong to different set</em>

8 0

2 years ago

Need help with all them, state how you know also<br><br> Triangle Congruency

nata0808 [166]

Answer

where is the pdf?

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers