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2 years ago

4 times a number is subtracted from 7 to give 15

Mathematics

1 answer:

Umnica [9.8K]2 years ago

4 0

I believe it’s 7-4x=15 and x= -2

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Is (-2) with the exponent 9 positive or negative

antiseptic1488 [7]

Answer:

negative

Step-by-step explanation:

A negative value raised to an even exponent is positive

A negative value raised to an odd exponent is negative

$(-2)^{9}$ = - 512 ← negative

$(-2)^{8}$ = 256 ← positive

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3 years ago

An ore is 0.75% pure gold. How many kilograms of gold are in 500 kg of ore?

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0.75 x 500 is 375 of gold in 500 kg of ore

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2 years ago

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iVinArrow [24]

Answer:

3x-12 is the simplififed answer

Step-by-step explanation:

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2 years ago

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3 years ago

The spherical balloon is inflated at the rate of 10 m³/sec. Find the rate at which the surface area is increasing when the radiu

rjkz [21]

The balloon has a volume $V$ dependent on its radius $r$ :

$V(r)=\dfrac43\pi r^3$

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$\dfrac{\mathrm dV}{\mathrm dt}=4\pi r^2\dfrac{\mathrm dr}{\mathrm dt}$

If the volume is increasing at a rate of 10 cubic m/s, then at the moment the radius is 3 m, it is increasing at a rate of

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and differentiating gives

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so that at the moment the radius is 3 m, its area is increasing at a rate of

$\dfrac{\mathrm dS}{\mathrm dt}=8\pi(3\,\mathrm m)\left(\dfrac5{18\pi}\dfrac{\rm m}{\rm s}\right)=\dfrac{20}3\dfrac{\mathrm m^2}{\rm s}$

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2 years ago

4 times a number is subtracted from 7 to give 15​

4 times a number is subtracted from 7 to give 15