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2 years ago

3x+3y=27 3x-3y= -11 using elimination

1 answer:

Taya2010 [7]2 years ago

3 0

3x + 3y = 27
3x - 3y = -11
------------------add
6x = 16
x = 16/6 which reduces to 8/3

3x + 3y = 27
3(8/3) + 3y = 27
8 + 3y = 27
3y = 27 - 8
3y = 19
y = 19/3

solution is (8/3, 19/3)

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If 7% of Americans is about 22 million, which number below could represent 7% of Americans

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3 years ago

Need help with the question in the picture learned awhile ago and forget!

xxTIMURxx [149]

Answer:

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2 years ago

Please help me out!

seropon [69]

Answer:

Second option

Third option

Fourth option

Step-by-step explanation:

We have the following quadratic function

$f(x) =(x-1)(x+7)$

Use the distributive property to multiply the expression

$f(x) =x^2+7x-x-7$

$f(x) =x^2+6x-7$

For a function of the form $f (x) = ax ^ 2 + bx + c$ the x coordinate of the vertex is:

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Then in this case the coordinate of the vertex is:

$x =-\frac{6}{2(1)}$

$x =-3$

To obtain the y coordinate of the vertex we evaluate the function at $x = -3$

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Then the vertex is: (-3, -16)

We can see in the graph that the zeros of the function are x=1 and x=-7

Then the function is decreasing from -∞ to -3 and then it is increasing from -3 to ∞

The function is positive for $x$ and $x> 1$

The correct answers are:

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7 0

3 years ago

Compound interest of $1000 is invested at 10% compounded continuously, the future value s at any time t in years is given by s=1

crimeas [40]

Answer: 6.93 years

Step-by-step explanation:

Given

Rate of interest is $r=10\%$

Future value is given by $s=1000e^{0.1t}$

For the investment to double itself, i.e. $s=2000$

$\Rightarrow 2000=1000e^{0.1t}\\\Rightarrow 2=e^{0.1t}\\\\\text{Taking log both sides}\\\\\Rightarrow \ln 2=0.1t\\\\\Rightarrow t=\dfrac{\ln 2}{0.1}\\\\\Rightarrow t=6.93\ \text{years}$

It takes around 6.93 years to double the investment.

8 0

2 years ago

The equation tan^2 x+1=sec^2 x is an identity true or false

Solnce55 [7]

Answer:

tan²x + 1 = sec²x is identity

Step-by-step explanation:

* Lets explain how to find this identity

∵ sin²x + cos²x = 1 ⇒ identity

- Divide both sides by cos²x

∵ sin x ÷ cos x = tan x

∴ sin²x ÷ cos²x = tan²x

- Lets find the second term

∵ cos²x ÷ cos²x = 1

- Remember that the inverse of cos x is sec x

∵ sec x = 1/cos x

∴ sec²x = 1/cos²x

- Lets write the equation

∴ tan²x + 1 = 1/cos²x

∵ 1/cos²x = sec²x

∴ than²x + 1 = sec²x

- So we use the first identity sin²x + cos²x = 1 to prove that

tan²x + 1 = sec²x

∴ tan²x + 1 = sec²x is identity

8 0

3 years ago