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3 years ago

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

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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Express in logarithmic form for the base. x y = P

denis-greek [22]

So

$x^y=P$

remember
$a^b=c$ translates to $log_a(c)=b$
basically, the power that a must be raised to to obtain c is b

so
$x^y=P$ translates to $log_x(P)=y$

8 0

3 years ago

Read 2 more answers

Factor the equation x^2 -7x+10

Maslowich

Answer:

(x - 5)(x - 2)

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3 years ago

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

:.n=-1

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

c=5

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

={-1±√-39}/2

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?

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

Avg speed for the round trip = 2*75*40/(75+40) = 6000/115 = 1200/23 mi/hr

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