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3 years ago

9

How many gallons of 80% antifreeze solution must be mixed with 80gallons of 20% antifreeze to get a mixture that is 70% antifree

ze

1 answer:

kvasek [131]3 years ago

5 0

X=360 GALLONS OF 80% ANTIFREEZE IS USED

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Help a brother out, I'm lost

9966 [12]

Answer:

I think that the answer is 25,180.

Step-by-step explanation:

8 0

3 years ago

Which statements about the system are true? Select two options.

kondor19780726 [428]

Answer:

The system consists of parallel lines, and the both lines have the same slope.

Step-by-step explanation:

The slope is the coefficient of x. (The coefficient of y should be 1)

When the slopes are equal, it means they are parallel.

8 0

3 years ago

Please help me to prove this!

Sophie [7]

Answer: see proof below

<u>Step-by-step explanation:</u>

Given: A + B = C → A = C - B

→ B = C - A

Use the Double Angle Identity: cos 2A = 2 cos² A - 1

→ (cos 2A + 1)/2 = cos² A

Use Sum to Product Identity: cos A + cos B = 2 cos [(A + B)/2] · 2 cos [(A - B)/2]

Use Even/Odd Identity: cos (-A) = cos (A)

<u>Proof LHS → RHS:</u>

LHS: cos² A + cos² B + cos² C

$\text{Double Angle:}\qquad \dfrac{\cos 2A+1}{2}+\dfrac{\cos 2B+1}{2}+\cos^2 C\\\\\\.\qquad \qquad \qquad =\dfrac{1}{2}\bigg(2+\cos 2A+\cos 2B\bigg)+\cos^2 C\\\\\\.\qquad \qquad \qquad =1+\dfrac{1}{2}\bigg(\cos 2A+\cos 2B\bigg)+\cos^2 C$

$\text{Sum to Product:}\quad 1+\dfrac{1}{2}\bigg[2\cos \bigg(\dfrac{2A+2B}{2}\bigg)\cdot \cos \bigg(\dfrac{2A-2B}{2}\bigg)\bigg]+\cos^2 C\\\\\\.\qquad \qquad \qquad =1+\cos (A+B)\cdot \cos (A-B)+\cos^2 C$

$\text{Given:}\qquad \qquad 1+\cos C\cdot \cos (A-B)+\cos^2C$

$\text{Factor:}\qquad \qquad 1+\cos C[\cos (A-B)+\cos C]$

$\text{Sum to Product:}\quad 1+\cos C\bigg[2\cos \bigg(\dfrac{A-B+C}{2}\bigg)\cdot \cos \bigg(\dfrac{A-B-C}{2}\bigg)\bigg]\\\\\\.\qquad \qquad \qquad =1+2\cos C\cdot \cos \bigg(\dfrac{A+(C-B)}{2}\bigg)\cdot \cos \bigg(\dfrac{-B-(C-A)}{2}\bigg)$

$\text{Given:}\qquad \qquad =1+2\cos C\cdot \cos \bigg(\dfrac{A+A}{2}\bigg)\cdot \cos \bigg(\dfrac{-B-B}{2}\bigg)\\\\\\.\qquad \qquad \qquad =1+2\cos C \cdot \cos A\cdot \cos (-B)$

$\text{Even/Odd:}\qquad \qquad 1+2\cos C \cdot \cos A\cdot \cos B\\\\\\.\qquad \qquad \qquad \quad =1+2\cos A \cdot \cos B\cdot \cos C$

LHS = RHS: 1 + 2 cos A · cos B · cos C = 1 + 2 cos A · cos B · cos C $\checkmark$

5 0

3 years ago

Greeley [361]

$f(x) = {x}^{7}$

$g(x) = 3x + 3$

_________________________________

$f(x) = {x}^{14}$

$g(x) = \sqrt{3x + 3}$

_________________________________

$f(x) = ({5x - 10})^{7}$

$g(x) = \frac{3}{5}x + \frac{13}{5} \\$

_________________________________

And many other answers....

3 0

3 years ago

HELP PLZZ ANYONE OUT THEIR

Paraphin [41]

I think I only know the decimals, for quarters there is three quarters with equals 75 cents so that would be .75 for dime a dime equals ten cents so that would be .10 and for. Nickels 6 nickels equals thirty cents so the decimal would be .30

3 0

3 years ago