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4 years ago

Please help . tjjhhhhhhhh

Mathematics

2 answers:

natka813 [3]4 years ago

7 0

Answer:

19 - 8√3

Step-by-step explanation:

(-4 + √2)^2

= (-4)^2 + 2(-4)(√3) + √3)^2

= 16 - 8√3 + 3

= 19 - 8√3

Crank4 years ago

6 0

Answer:

Step-by-step explanation:

note that ( $\sqrt{3}$ )² = 3

Given

(- 4 + $\sqrt{3}$ )² = (- 4 + $\sqrt{3}$ )(- 4 + $\sqrt{3}$ )

Expand using (a + b)² = a² + 2ab + b²

= (- 4 )² + 2(- 4 $\sqrt{3}$ ) + ( $\sqrt{3}$ )²

= 16 - 8 $\sqrt{3}$ + 3

= 19 - 8 $\sqrt{3}$

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Answer: the cost per unit of gas is $0.28

Step-by-step explanation:

Let x represent the cost per unit of electricity.

Let y represent the cost per unit of gas.

During one month, a homeowner used 500 units of electricity and 100 units of gas for a total cost of $333. This is expressed as

500x + 100y = 333 - - - -- - -- - -- -1

The next month, 400 units of electricity and 150 units of gas were used for a total cost of $286. This is expressed as

400x + 150y = 286 - - - - - - - - - --2

Multiplying equation 1 by 400 and equation 2 by 500, it becomes

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3 years ago

If sin(x) =-1/2 and tan(x) is negative what is cos(2x)

Keith_Richards [23]

Answer:

positive

Step-by-step explanation:

Using the acronym ASTC (all students take calculus), this means that if sin and tan are negative, they must be in the fourth quadrant, which means that cos is positive.

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A: all

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T: tan

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4 years ago

Need help asap. Will mark brainliest.

ZanzabumX [31]

Answer:

$X=\begin{bmatrix}17 &3 \\-24 &-12 \\3 &-16 \end{bmatrix}$

Step-by-step explanation:

Matrix Equations

Given:

$A=\begin{bmatrix}-7 &-2 \\9 &7 \\2 &4 \end{bmatrix}$

$B=\begin{bmatrix}-4 &-3 \\3 &9 \\9 &-4 \end{bmatrix}$

Find X such that:

B - X = 3A

Subtracting B:

- X = 3A - B

Multiplying by -1:

X = -3A + B

Find -3A:

$-3A=-3\begin{bmatrix}-7 &-2 \\9 &7 \\2 &4 \end{bmatrix}=\begin{bmatrix}21 &6 \\-27 &-21 \\-6 &-12 \end{bmatrix}$

Add to B:

$X=-3A+B=\begin{bmatrix}21 &6 \\-27 &-21 \\-6 &-12 \end{bmatrix}+\begin{bmatrix}-4 &-3 \\3 &9 \\9 &-4 \end{bmatrix}=\begin{bmatrix}17 &3 \\-24 &-12 \\3 &-16 \end{bmatrix}$