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3 years ago

If Y varies directly with X solve the following :

Mathematics

1 answer:

BARSIC [14]3 years ago

5 0

Answer:

a) x = -270

b) y = 304/9 or y = 33.78

c) x = -37.8

Step-by-step explanation:

y varies directly with x so y = kx

y = kx

k = y/x

k = 10/-30 = -1/3

y = -1/3 x

If y = 90 then

90 = -1/3 x

x = 90 *(-3) = -270

k = y/x

k = -19/-4.5

k = 38/9

y = 38/9 x

If x = - 8 then

y = 38/9 *(-8)

y = 304/9 or y = 33.78

k = y/x

k = -4.3 / 12.9

k = - 1/3

y = -1/3 x

If y = 12.6 then

12.6 = -1/3 x

x = 12.6 *(-3)

x = -37.8

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Solve for

Lubov Fominskaja [6]

Answer:

x = 3/2

Step-by-step explanation:

2(x + 5) = 6x + 4

Open bracket first

2 × x + 2×5 = 6x + 4

2x + 10 = 6x + 4

Rewrite equation

6x + 4 = 2x + 10

Subtract 2x from both sides

6x - 2x + 4 = 2x - 2x + 10

4x + 4 = 10

Subtract 4 from both sides

4x + 4 - 4 = 10 - 4

4x = 6

Divide both sides by 4

4x/4 = 6/4

x = 6/4

Divide both denominator and numerator by 2

x = (6/4) ÷ 2

x = 3/2

I hope this was helpful, please rate as brainliest

7 0

3 years ago

Which do the following options represent the measure of arc RA

ANTONII [103]

Answer:

77.2°

Step-by-step explanation:

Consider the triangle JKR.

∠KJR=108.6 (lies on the same line as ∠RJA, angles on a straight line add up to 180)

All the angles in a triangle add up to 180, so:

∠JKR+∠KJR+∠JRK=180

∠JKR+108.6+32.8=180

∠JKR=38.6=∠RKA

Consider ∠RKA. This angle stands on the same arc as ∠RCA.

Since the angle at centre is twice the angle at circumference, 2(∠RKA) = ∠RCA.

2(∠RKA) = ∠RCA

2(38.6)=∠RCA

∠RCA=77.2°

5 0

2 years ago

PLEASE HELP WILL GIVE BRAINLIEST AND POINTS

ZanzabumX [31]

Answer:

bcdf

Step-by-step explanation:

here ya go

4 0

3 years ago

The number of bacteria after t hours is given by N(t)=250 e^0.15t a) Find the initial number of bacteria and the rate of growth

Art [367]

Answer:

a) $N_0=250\; k=0.15$

b) 334,858 bacteria

c) 4.67 hours

d) 2 hours

Step-by-step explanation:

a) Initial number of bacteria is the coefficient, that is, 250. And the growth rate is the coefficient besides “t”: 0.15. It’s rate of growth because of its positive sign; when it’s negative, it’s taken as rate of decay.

Another way to see that is the following:

Initial number of bacteria is N(0), which implies $t=0$ . And $N(0)=N_0$ . The process is:

$N(t)=250 e^{0.15t}\\N(0)=250 e^{0.15(0)}\\ N_0=250e^{0}\\N_0=250\cdot1\\ N_0=250$

b) After 2 days means $t=48$ . So, we just replace and operate:

$N(t)=250 e^{0.15t}\\N(48)=250 e^{0.15(48)}\\ N(48)=250e^{7.2}\\N(48)=334,858\;\text{bacteria}$

c) $N(t_1)=4000; \;t_1=?$

$N(t)=250 e^{0.15t}\\4000=250 e^{0.15t_1}\\ \dfrac{4000}{250}= e^{0.15t_1}\\16= e^{0.15t_1}\\ \ln{16}= \ln{e^{0.15t_1}} \\ \ln{16}=0.15t_1 \\ \dfrac{\ln{16}}{0.15}=t_1=4.67\approx 5\;h$