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3 years ago

15

2x + y = -8 3x - 5y = -25

1 answer:

Margarita [4]3 years ago

6 0

Answer:

x=-5, y=2. (-5, 2).

Step-by-step explanation:

2x+y=-8

3x-5y=-25

------------------

5(2x+y)=5(-8)

3x-5y=-25

-------------------

10x+5y=-40

3x-5y=-25

--------------------

13x=-65

x=-65/13

x=-5

2(-5)+y=-8

-10+y=-8

y=-8-(-10)=-8+10=2

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Please help do tmrw

iren2701 [21]

Answer:

One is 3x+2 while the other is 2x-1

Step-by-step explanation:

It is opposite to one another

the one with 3x+2 is opposite to the non given one and the one withb2x-1 is opposite

5 0

2 years ago

Solve the oblique triangle where side a has length 10 cm, side c has length 12 cm, and angle beta has measure thirty degrees. Ro

Ugo [173]

Answer:

$Side\ B = 6.0$

$\alpha = 56.3$

$\theta = 93.7$

Step-by-step explanation:

Given

Let the three sides be represented with A, B, C

Let the angles be represented with $\alpha, \beta, \theta$

[See Attachment for Triangle]

$A = 10cm$

$C = 12cm$

$\beta = 30$

What the question is to calculate the third length (Side B) and the other 2 angles ( $\alpha\ and\ \theta$ )

Solving for Side B;

When two angles of a triangle are known, the third side is calculated as thus;

$B^2 = A^2 + C^2 - 2ABCos\beta$

Substitute: $A = 10$ , $C =12$ ; $\beta = 30$

$B^2 = 10^2 + 12^2 - 2 * 10 * 12 *Cos30$

$B^2 = 100 + 144 - 240*0.86602540378$

$B^2 = 100 + 144 - 207.846096907$

$B^2 = 36.153903093$

Take Square root of both sides

$\sqrt{B^2} = \sqrt{36.153903093}$

$B = \sqrt{36.153903093}$

$B = 6.0128115797$

$B = 6.0$ <em>(Approximated)</em>

Calculating Angle $\alpha$

$A^2 = B^2 + C^2 - 2BCCos\alpha$

Substitute: $A = 10$ , $C =12$ ; $B = 6$

$10^2 = 6^2 + 12^2 - 2 * 6 * 12 *Cos\alpha$

$100 = 36 + 144 - 144 *Cos\alpha$

$100 = 36 + 144 - 144 *Cos\alpha$

$100 = 180 - 144 *Cos\alpha$

Subtract 180 from both sides

$100 - 180 = 180 - 180 - 144 *Cos\alpha$

$-80 = - 144 *Cos\alpha$

Divide both sides by -144

$\frac{-80}{-144} = \frac{- 144 *Cos\alpha}{-144}$

$\frac{-80}{-144} = Cos\alpha$

$0.5555556 = Cos\alpha$

Take arccos of both sides

$Cos^{-1}(0.5555556) = Cos^{-1}(Cos\alpha)$

$Cos^{-1}(0.5555556) = \alpha$

$56.25098078 = \alpha$

$\alpha = 56.3$ <em>(Approximated)</em>

Calculating $\theta$

Sum of angles in a triangle = 180

Hence;

$\alpha + \beta + \theta = 180$

$30 + 56.3 + \theta = 180$

$86.3 + \theta = 180$

Make $\theta$ the subject of formula

$\theta = 180 - 86.3$

$\theta = 93.7$

5 0

3 years ago

Which ordered pair is a solution to the system of equations?

melisa1 [442]

Answer:

(-2, -3)

Step-by-step explanation:

We assume your system of equations is ...

2x - y = -1
2x -4y = 8

You can subtract the second equation from the first to get

... (2x -y) -(2x -4y) = (-1) -(8)

... 3y = -9 . . . . . collect terms

... y = -3 . . . . . . divide by 3 . . . . this is sufficient to identify the correct answer

Substituting into the first equation, we have ...

... 2x -(-3) = -1

... 2x = -4 . . . . . add -3

... x = -2 . . . . . . .divide by 2

Now, we're sure the answer is (x, y) = (-2, -3).

3 0

3 years ago

Twelve subtracted from two times a number is -70. What is the number?

gtnhenbr [62]

x = 6

Step-by-step explanation:

2 - 12 × x = -70

= -12x +2 = -70

4 0

3 years ago

4x^2(7x^3-6x^2+5x-7)

Shkiper50 [21]

Hope this helps you!

4 0

3 years ago