All categories

3 years ago

-2(7a+ 9b) = –14a + [?]b

Mathematics

2 answers:

MariettaO [177]3 years ago

4 0

Answer:

the unknown, [?], has the value -18.

Step-by-step explanation:

Perform the indicated multiplication on the left side:

-14a - 18b = -14a + [?]b

Adding 14a to both sides, we eliminate a:

-18b = [?]b

Thus, the unknown, [?], has the value -18.

OverLord2011 [107]3 years ago

3 0

Answer:

-18

Step-by-step explanation:

Left Hand Side = -2(7a + 9b) = -14a - 18b

Comparing it with Right Hand Side, ? = -18

You might be interested in

Carly owns a toy store. She sells teddy bears and charges $25 per bear. Her total monthly cost is $3765. How many bears does Car

Zinaida [17]

Answer:

divide 3765 by 25 to get how many bears she sold, then divide that by 3765

3 0

2 years ago

Read 2 more answers

Please help with this 1 question it's 20 points.

Elden [556K]

JIG is clockwise around the figure, as is DEF, so there is no reflection involved. The midpoint between any two corresponding vertices is (1, 4), so that is the center of rotation. Figure DEF is "upside down" from JIG, so rotation is 180°.

The 1st selection is appropriate.

7 0

3 years ago

Read 2 more answers

WILL GIVE BRAINLIEST!! What are the slope and the y-intercept of the linear function that is represented by the graph?

UNO [17]

Answer:

its d

Step-by-step explanation:

y=-3/4+3 I think that's right

3 0

3 years ago

Read 2 more answers

The radius of a cone is increasing at a constant rate of 7 meters per minute, and the volume is decreasing at a rate of 236 cubi

storchak [24]

Answer:

The rate of change of the height is 0.021 meters per minute

Step-by-step explanation:

From the formula

$V = \frac{1}{3}\pi r^{2}h$

Differentiate the equation with respect to time t, such that

$\frac{d}{dt} (V) = \frac{d}{dt} (\frac{1}{3}\pi r^{2}h)$

$\frac{dV}{dt} = \frac{1}{3}\pi \frac{d}{dt} (r^{2}h)$

To differentiate the product,

Let r² = u, so that

$\frac{dV}{dt} = \frac{1}{3}\pi \frac{d}{dt} (uh)$

Then, using product rule

$\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h\frac{du}{dt}]$

Since $u = r^{2}$

Then, $\frac{du}{dr} = 2r$

Using the Chain's rule

$\frac{du}{dt} = \frac{du}{dr} \times \frac{dr}{dt}$

∴ $\frac{dV}{dt} = \frac{1}{3}\pi [u\frac{dh}{dt} + h(\frac{du}{dr} \times \frac{dr}{dt})]$

Then,

$\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]$

Now,

From the question

$\frac{dr}{dt} = 7 m/min$

$\frac{dV}{dt} = 236 m^{3}/min$

At the instant when $r = 99 m$

and $V = 180 m^{3}$

We will determine the value of h, using

$V = \frac{1}{3}\pi r^{2}h$

$180 = \frac{1}{3}\pi (99)^{2}h$

$180 \times 3 = 9801\pi h$

$h =\frac{540}{9801\pi }$

$h =\frac{20}{363\pi }$

Now, Putting the parameters into the equation

$\frac{dV}{dt} = \frac{1}{3}\pi [r^{2} \frac{dh}{dt} + h(2r) \frac{dr}{dt}]$

$236 = \frac{1}{3}\pi [(99)^{2} \frac{dh}{dt} + (\frac{20}{363\pi }) (2(99)) (7)]$

$236 \times 3 = \pi [9801 \frac{dh}{dt} + (\frac{20}{363\pi }) 1386]$

$708 = 9801\pi \frac{dh}{dt} + \frac{27720}{363}$

$708 = 30790.75 \frac{dh}{dt} + 76.36$

$708 - 76.36 = 30790.75\frac{dh}{dt}$

$631.64 = 30790.75\frac{dh}{dt}$

$\frac{dh}{dt}= \frac{631.64}{30790.75}$

$\frac{dh}{dt} = 0.021 m/min$

Hence, the rate of change of the height is 0.021 meters per minute.

3 0

3 years ago

"Gina wrote the following paragraph to prove that the segment joining the midpoints of two sides of a triangle is parallel to th

Aleonysh [2.5K]

What is the flaw in Gina’s proof?
A) Points D and E must be constructed, not simply labeled, as midpoints.

B) Segments DE and AC are parallel by construction. THIS IS THE FLAW. THE SEGMENTS WERE NOT DRAWN NOR PROPERLY IDENTIFIED.

C) The slope of segments DE and AC is not 0.

D) The coordinates of D and E were found using the Distance between Two Points Postulate

6 0

3 years ago

Read 2 more answers