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Mandarinka [93]
3 years ago
5

Please answer below :-)

Mathematics
1 answer:
Serjik [45]3 years ago
7 0

Answer:

B. 88.8

Step-by-step explanation:

let x represent class y

(x+71.2)/2=80   multiply each side by 2

x+71.2=160      subtract 71.2 by both sides

x=88.8

or

trial an error

replace x with each of the numbers and see if it plugs in.

example:

(80.5+71.2)/2=80

151.7/2=80

75.85=80?

false. incorrect

another example:

(88.8+71.2)/2=80

160/2=80

80=80?

true. correct

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So

x^y=P

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a^b=c translates to log_a(c)=b
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so
x^y=P translates to log_x(P)=y
8 0
3 years ago
Read 2 more answers
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Maslowich

Answer:

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Use a half-angle identity to find the exact value
Tatiana [17]

Given:

\cos 15^{\circ}

To find:

The exact value of cos 15°.

Solution:

$\cos 15^{\circ}=\cos\frac{ 30^{\circ}}{2}

Using half-angle identity:

$\cos \left(\frac{x}{2}\right)=\sqrt{\frac{1+\cos (x)}{2}}

$\cos \frac{30^{\circ}}{2}=\sqrt{\frac{1+\cos \left(30^{\circ}\right)}{2}}

Using the trigonometric identity: \cos \left(30^{\circ}\right)=\frac{\sqrt{3}}{2}

            $=\sqrt{\frac{1+\frac{\sqrt{3}}{2}}{2}}

Let us first solve the fraction in the numerator.

            $=\sqrt{\frac{\frac{2+\sqrt{3}}{2}}{2}}

Using fraction rule: \frac{\frac{a}{b} }{c}=\frac{a}{b \cdot c}

            $=\sqrt{\frac {2+\sqrt{3}}{4}}

Apply radical rule: \sqrt[n]{\frac{a}{b}}=\frac{\sqrt[n]{a}}{\sqrt[n]{b}}

           $=\frac{\sqrt{2+\sqrt{3}}}{\sqrt{4}}

Using \sqrt{4} =2:

           $=\frac{\sqrt{2+\sqrt{3}}}{2}

$\cos 15^\circ=\frac{\sqrt{2+\sqrt{3}}}{2}

5 0
3 years ago
Without solving determine the number of real solutions for each quadratic equation
snow_lady [41]

Step-by-step explanation:

b^2-4b+3=0

b²-3x-b+3=0

b(b-3)-1(b-3)=0

(b-3)(b-1)=0

either

b=3 or b=1

.

2n^2 + 7 = -4n + 5

2n²+4n+7-5=0

2n²+4n+2=0

2(n²+2n+1)=0

(n+1)²=0/2

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.

x - 3x^2 = 5+ 2x - x^2

0=5+ 2x - x^2-x +3x^2

0=5+x+2x²

2x²+x+5=0

comparing above equation with ax²+bx +c we get

a=2

b=1

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x={-b±√(b²-4ac)}/2a ={-1±√(1²-4×2×5)}/2×1

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8 0
2 years ago
Bob drove from home to work at 75 mph.After work the traffic was heavier,and he drove home at 40 mph.His driving time to and fro
Ilya [14]

Answer:

Bob drove from home to work at 75 mph. After work the traffic was heavier, and he drove home at 40 mph. His driving time to and from work was 1 hour and 9 minutes. How far does he live from his job?

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

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RT distance = 1200/23 * 69 minutes * 1 hr/60 mins =

= 60 miles

30 miles each way

Step-by-step explanation:

4 0
3 years ago
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