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inna [77]
3 years ago
10

Solve the following system of equations. Express your answer as an ordered pair in the format (a,b), with no spaces between the

numbers or symbols
2x+7y=-1 and 4x-3y=-19
Mathematics
2 answers:
AVprozaik [17]3 years ago
7 0
Multiply the equation 2x+7y=-1 by -2

add to othe equaiton
4x-3y=-19
<u>-4x-14y=2 +</u>
0x-17y=-17

-17y=-17
divide both sides by -17
y=1

sub back
2x+7y=-1
2x+7(1)=-1
2x+7=-1
minus 7 from both sides
2x=-8
divide both sides by 2
x=-4

x=-4
y=1
(x,y) is normal form
(-4,1) is answer
zzz [600]3 years ago
7 0

Answer:

The answer is (-4,1)

Step-by-step explanation:

You might be interested in
In the diagram abc=adb=90, ad=p and dc=q. Use similar triangles to show that x2=pz<br> plzz anyoneee
kramer

Answer:

By comparing the ratios of sides in similar triangles ΔABC and ΔADB,we can say that x^{2} =pz

Step-by-step explanation:

Given that ∠ABC=∠ADC, AD=p and DC=q.

Let us take compare Δ ABC and  Δ ADB in the attached file , ∠A is common in both triangles

                                                                     and given ∠ABC=∠ADB=90°

Hence using AA postulate, ΔABC ≈ ΔADB.

Now we will equate respective side ratios in both triangles.

\frac{AB}{AC}= \frac{AD}{AB}=\frac{BD}{BC}

Since we don't know BD , BC let us take first equality and plugin the variables given in respective sides.

\frac{x}{z}= \frac{p}{x}

Cross multiply

x^{2}=pz

Hence proved.


7 0
4 years ago
Help me pleasee (10 points)
Montano1993 [528]

Answer:

B

Step-by-step explanation:

Givens

a^2 + b^2 = c^2

a = 4x

b = x + 2

c = 3x + 4

Solution

(4x)^2 + (x + 2)^2 = (3x + 4)^3                  Remove all the brackets.

16x^2 + x^2 + 4x + 4 = 9x^2 + 24x + 16  Collect like terms on the left

17x^2 + 4x + 4 = 9x^2 + 24x + 16            Subtract the terms on the right

8x^2 - 20x - 12 = 0

This factors into

(4x - 12)(2x + 1)

There are 2 answers

4x - 12 = 0

4x = 12

x = 12/4

x = 3

or

2x + 1 = 0

2x = - 1

x = - 1/2

You have to look at x = -1/2 carefully. The problem is that 4x = 4*(-1/2) = - 2 which is not possible in Euclidean Geometry.

So the only answer is x = 3

4 0
3 years ago
What is the approximate area of the shaded portion of the diagram? (Use 3.14 as an estimate for pi.)
Nadusha1986 [10]

Answer:

218

Step-by-step explanation:

first find the area of the circle-

A=\pi r^{2} \\A=\pi 10^{2} \\A=100\pi \\A=314

to find the area of the triangle, we need the base and the height. The base we know is 16, since we don't know the height yet, use the Pythagorean theorem to find the height. One leg is 16 the hypotenuse is 20 (2* the radius).

a^{2} +b^{2} =c^{2} \\a^{2} +16^{2} =20^{2} \\a^{2} +256=400\\a^{2} =144\\a=12

Now I know the height is 12. Find the area of the triangle

A=\frac{1}{2} bh\\A=\frac{1}{2} (16)(20)\\A=96

subtract the area of the triangle from the area of the circle

314-96=218

6 0
3 years ago
A researcher compares the effectiveness of two different instructional methods for teaching electronics. A sample of 138 student
yan [13]

Answer:

The 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 is (-8.04, 0.84).

Step-by-step explanation:

The (1 - <em>α</em>)% confidence interval for the difference between population means is:

CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}

The information provided is as follows:

n_{1}= 138\\n_{2}=156\\\bar x_{1}=61\\\bar x_{2}=64.6\\\sigma_{1}=18.53\\\sigma_{2}=13.43

The critical value of <em>z</em> for 98% confidence level is,

z_{\alpha/2}=z_{0.02/2}=2.326

Compute the 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 as follows:

CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}

     =(61-64.6)\pm 2.326\times\sqrt{\frac{(18.53)^{2}}{138}+\frac{(13.43)^{2}}{156}}\\\\=-3.6\pm 4.4404\\\\=(-8.0404, 0.8404)\\\\\approx (-8.04, 0.84)

Thus, the 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 is (-8.04, 0.84).

5 0
3 years ago
What is the following fraction in simplest form 4/16
ladessa [460]

Answer:

1/4

Step-by-step explanation:

3 0
3 years ago
Read 2 more answers
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