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valentina_108 [34]

2 years ago

6

There are 20 students in a math class who have brown hair. This represents 80 percent of the students in the class. Which equati

on can be used to find the total number of students in the math class? 20 x 100 2000 80x 100 2000 E 400 80 x 5 20x5 90-4 100=4 25 20-120 80-180

2 answers:

Reptile [31]2 years ago

5 0

Answer:

The answer is C

Step-by-step explanation:

JulsSmile [24]2 years ago

5 0

Answer:

C

Step-by-step explanation:

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inessss [21]

Answer:

I believe it is 2 so X=2

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3 years ago

Write 13/40 as a decimal?

borishaifa [10]

0.325 is the answer. :)

6 0

3 years ago

Read 2 more answers

Find the roots of the equation<br> x ^ 2 + 3x-8 ^ -14 = 0 with three precision digits

scoray [572]

Answer:

Step-by-step explanation:

Given quadratic equation:

$x^{2} + 3x - 8^{- 14} = 0$

The solution of the given quadratic eqn is given by using Sri Dharacharya formula:

$x_{1, 1'} = \frac{- b \pm \sqrt{b^{2} - 4ac}}{2a}$

The above solution is for the quadratic equation of the form:

$ax^{2} + bx + c = 0$

$x_{1, 1'} = \frac{- b \pm \sqrt{b^{2} - 4ac}}{2a}$

From the given eqn

a = 1

b = 3

c = $- 8^{- 14}$

Now, using the above values in the formula mentioned above:

$x_{1, 1'} = \frac{- 3 \pm \sqrt{3^{2} - 4(1)(- 8^{- 14})}}{2(1)}$

$x_{1, 1'} = \frac{1}{2} (\pm \sqrt{9 - 4(1)(- 8^{- 14})})$

$x_{1, 1'} = \frac{1}{2} (\pm \sqrt{9 - 4(1)(- 8^{- 14})} - 3)$

Now, Rationalizing the above eqn:

$x_{1, 1'} = \frac{1}{2} (\pm \sqrt{9 - 4(- 8^{- 14})} - 3)\times (\frac{\sqrt{9 - 4(- 8^{- 14})} + 3}{\sqrt{9 - 4(- 8^{- 14})} + 3}$

$x_{1, 1'} = \frac{1}{2}.\frac{(\pm {9 - 4(- 8^{- 14})^{2}} - 3^{2})}{\sqrt{9 - 4(- 8^{- 14})} + 3}$

Solving the above eqn:

$x_{1, 1'} = \frac{2\times 8^{- 14}}{\sqrt{9 + 4\times 8^{-14}} + 3}$

Solving with the help of caculator:

$x_{1, 1'} = \frac{2\times 2.27\times 10^{- 14}}{\sqrt{9 + 42.27\times 10^{- 14}} + 3}$

The precise value upto three decimal places comes out to be:

$x_{1, 1'} = 0.758\times 10^{- 14}$

5 0

3 years ago

In each part that follows, you are given an equation of a line and a point. Find the equation of the line through the given poi

Semmy [17]

Answer:

a) $y=-\frac{1}{9}x$

b) $y-2=-\frac{1}{3} (x-1)$

Step-by-step explanation:

We can write the equation of a line in 3 different forms including slope intercept, point-slope, and standard depending on the information we have. We have a point given and a slope from the equation. We will chose point-slope since we have a point and can find the slope.

Point slope: $y-y_1=m(x-x_1)$

a) $m\neq 9$ in our new equation because it is perpendicular to it. This means we will need to change it into its negative reciprocal which is $m=-\frac{1}{9}$ .

We will substitute $m=-\frac{1}{9}$ and $x_1=0\\y_1=0$ .

$y-0=-\frac{1}{9} (x-0)$

This simplifies to:

$y=-\frac{1}{9}x$

b) The equation y=3x+4 follows y=mx+b. For the perpendicular line, $m\neq 3$ . We will need to change it into its negative reciprocal which is $m=-\frac{1}{3}$ .

We will substitute $m=-\frac{1}{3}$ and $x_1=1\\y_1=2$ .

$y-2=-\frac{1}{3} (x-1)$

4 0

2 years ago

The minute hand of a watch has a length of 1.4 cm. Find the; (a) distance moved by the tip of the minute hand from 8.13 am to 8.

LenKa [72]

Answer:

A). The distance covered= 5.2752 cm

B). Angle swept = 36°

C). The time = 8:45 am

Step-by-step explanation:

The watch is assumed to be a circle while the minute hand is assumed to be the radius

Radius = 1.4cm

A). From 8:13 to 8:49= 36 minutes

Recall, there is 60 minutes in a round watch.

The distance covered= 2πr*36/60

The distance covered= 2*3.14*1.4*0.6

The distance covered= 5.2752 cm

B). If distance covered is 8.8 mm

8.8 mm = 0.88cm

0.88= 2*3.14*1.4*(x/360)

0.88/(8.792)=x/360

0.1= x/360

0.1= x/360

36°= x

Angle swept = 36°

C). The time it will be if the watch started from 8:39 am and moved 36°

36/360= y/60

0.1= y/60

0.1*60= y

6 minutes= y

The time with be 8:39+6 minutes

The time = 8:45 am

8 0

3 years ago