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2 years ago

Solve the system of equations. 7x + 6y = -1 --x + 2y = 3

Mathematics

1 answer:

Harrizon [31]2 years ago

7 0

Answer:

X=-1

Y=1

Solve using Elimination.

Step-by-step explanation:

Multiply the second equation by 7.

The two equations are now:

7x+6y=-1

-7x +14y=21

Combine the two equations

7x and -7x cancel each other out, 14y+6y is 20y, and 21 - 1 is 20.

The equation is now

20y=20, divide 20 on both sides to get Y=1.

Now, substitute 1 as Y in the second equation for -x+2(1)=3

-x+2=3, can be simplified, by subtracting 2 from both sides. Giving us

-x=1.

Divide both sides by -1 for X=-1

Final answers being X=-1, Y=1

Hope this helps! Let me know if you have further questions!

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3 years ago

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3 years ago

In the circle below, DB = 22 cm, and m<DBC = 60°. Find BC. Ignore my handwriting.

Karo-lina-s [1.5K]

Answer:

$BC=11\ cm$

Step-by-step explanation:

step 1

Find the measure of the arc DC

we know that

The inscribed angle measures half of the arc comprising

$m\angle DBC=\frac{1}{2}[arc\ DC]$

substitute the values

$60\°=\frac{1}{2}[arc\ DC]$

$120\°=arc\ DC$

$arc\ DC=120\°$

step 2

Find the measure of arc BC

we know that

$arc\ DC+arc\ BC=180\°$ ----> because the diameter BD divide the circle into two equal parts

$120\°+arc\ BC=180\°$

$arc\ BC=180\°-120\°=60\°$

step 3

Find the measure of angle BDC

we know that

The inscribed angle measures half of the arc comprising

$m\angle BDC=\frac{1}{2}[arc\ BC]$

substitute the values

$m\angle BDC=\frac{1}{2}[60\°]$

$m\angle BDC=30\°$

therefore

The triangle DBC is a right triangle ---> 60°-30°-90°

step 4

Find the measure of BC

we know that

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6 0

3 years ago

Question 1 (1 point)

olga55 [171]

Answer:

1) $2y^{2}+4y-9$

2) $18x^{5}y^{4}z$

3) $6x^{5}-12x^{4}+9x^{3}$

4) 40

5) $x^{3}-7x^{2}+3x+36$

Step-by-step explanation:

1) Distribute the negative sign that is outside the parentheses and then you must add like terms, as following:

$(y^{2}-3y-5)-(-y^{2}-7y+4)=y^{2}-3y-5+y^{2}+7y-4=2y^{2}+4y-9$

2) According to the Product property of exponents, when you multiply powers with the same base, you must add the exponents. Then:

$(6xy^{3}z)(3x^{2}yx^{2})=18x^{5}y^{4}z$

3) Apply the Distributive property and the Product property of exponents. Then, you obtain:

$-3x^{3}(-2x^{2}+4x-3)=6x^{5}-12x^{4}+9x^{3}$

4) $(4a+5)^{2}$ is a square of a sum, then, by definition you have:

$(a+b)^{2}=a^{2}+2ab+b^{2}$

Then:

$(4a+5)^{2}=(4a)^{2}+2(4a)(5)+5^{2}=16a^{2}+40a+25$

The coefficient of the second term is the number in front of the variable <em>a.</em> Then, the answer is: 40

5) Apply the Distributive property and the Product property of exponents, then, oyou must add the like terms:

$(x-4)(x^{2}-3x-9)=x^{3}-3x^{2}-9x-4x^{2}+12x+36=x^{3}-7x^{2}+3x+36$

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3 years ago