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3 years ago

Solve the simultaneous equation 2x - 5y = 9 3x + 4y = 2

Mathematics

1 answer:

lianna [129]3 years ago

8 0

Answer:

x = 2, y = -1.

Step-by-step explanation:

2x - 5y = 9

3x + 4y = 2

Multiply first equation by -3 and the second by 2:

-6x + 15y = -27

6x + 8y = 4 Adding the 2 equations:

23y = -23

y = -1.

Now substitute this value for y in the first equation:

2x - 5(-1) = 9

2x = 9 +5(-1)

2x = 9 - 5

2x = 4

x = 2.

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Let h(x)=20e^kx where k ɛ R (Picture attached. Thank you so much!)

zloy xaker [14]

Answer:

$k=0$

$\displaystyle \begin{aligned} 2k + 1& = 2\ln 20 + 1 \\ &\approx 2.3863\end{aligned}$

$\displaystyle \begin{aligned} k - 3&= \ln \frac{1}{2} - 3 \\ &\approx-3.6931 \end{aligned}$

Step-by-step explanation:

We are given the function:

$\displaystyle h(x) = 20e^{kx} \text{ where } k \in \mathbb{R}$

Given that h(1) = 20, we want to find k.

h(1) = 20 means that h(x) = 20 when x = 1. Substitute:

$\displaystyle (20) = 20e^{k(1)}$

Simplify:

$1= e^k$

Anything raised to zero (except for zero) is one. Therefore:

$k=0$

Given that h(1) = 40, we want to find 2k + 1.

Likewise, this means that h(x) = 40 when x = 1. Substitute:

$\displaystyle (40) = 20e^{k(1)}$

Simplify:

$\displaystyle 2 = e^{k}$

We can take the natural log of both sides:

$\displaystyle \ln 2 = \underbrace{k\ln e}_{\ln a^b = b\ln a}$

By definition, ln(e) = 1. Hence:

$\displaystyle k = \ln 2$

Therefore:

$2k+1 = 2\ln 2+ 1 \approx 2.3863$

Given that h(1) = 10, we want to find k - 3.

Again, this meas that h(x) = 10 when x = 1. Substitute:

$\displaystyle (10) = 20e^{k(1)}$

Simplfy:

$\displaystyle \frac{1}{2} = e^k$

Take the natural log of both sides:

$\displaystyle \ln \frac{1}{2} = k\ln e$

Therefore:

$\displaystyle k = \ln \frac{1}{2}$

Therefore:

$\displaystyle k - 3 = \ln\frac{1}{2} - 3\approx-3.6931$

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3 years ago

Solve for x and y 2x+3yi=-14+9i

ryzh [129]

2,314 is the anwser

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3 years ago

Given a temperature of 16°F, find the equivalent in °C.

Akimi4 [234]

Answer:

C = (5/9) (80 - 32) = (5/9) (48) = 26.66 °CStep-by-step explanation:

7 0

3 years ago

A farmer sells 7.7 kilograms of apples and pears at the farmer's market.

vagabundo [1.1K]

Answer:

She sold 5.775 kilograms of pears at the farmer's market.

Step-by-step explanation:

Let's first determine the information that the question gives us, and what we need to find.

Given:

The farmer sold 7.7 kilograms of apples and pears

1/4 of the weight is apples

The rest of the weight is pears

Find:

Kilograms of pears that the farmer sold

Start by finding the fraction of the whole weight that was pears...

$1-\frac{1}{4}=\frac{4}{4}-\frac{1}{4}=\frac{3}{4}$

Now, find 3/4 of 7.7...

$\frac{3}{4}(7.7)=\frac{23.1}{4}=5.775\ kg$

She sold 5.775 kilograms of pears at the farmer's market.

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2 years ago

Can someone show me the steps to solving this

Vaselesa [24]

Something like this or wtv

8 0

3 years ago