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3 years ago

-42/7 what is the answer

Mathematics

1 answer:

Sedbober [7]3 years ago

5 0

Answer: -6

Step-by-step explanation: the answer that's correct is -6. trust me. If you got it correct mark me brainlest.

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Solve using quadratic formula for 2x^(2)-10x+5=0

sergij07 [2.7K]

Answer:

$x=\frac{5+\sqrt{15}}{2},\:x=\frac{5-\sqrt{15}}{2}$

Step-by-step explanation:

$\mathrm{For\:a\:quadratic\:equation\:of\:the\:form\:}ax^2+bx+c=0\mathrm{\:the\:solutions\:are\:}$

$x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\mathrm{For\:}\quad a=2,\:b=-10,\:c=5$

$x_{1,\:2}=\frac{-\left(-10\right)\pm \sqrt{\left(-10\right)^2-4\cdot \:2\cdot \:5}}{2\cdot \:2}$

$\sqrt{\left(-10\right)^2-4\cdot \:2\cdot \:5}$

Apply exponent rule: (-a)^n=a^n, if n is even

$\left(-10\right)^2=10^2$

$=\sqrt{10^2-4\cdot \:2\cdot \:5}$

$\mathrm{Multiply\:the\:numbers:}\:4\cdot \:2\cdot \:5=40$

$=\sqrt{10^2-40}$

$10^2=100$

$=\sqrt{100-40}$

$\mathrm{Subtract\:the\:numbers:}\:100-40=60$

$=\sqrt{60}$

$60\:\mathrm{divides\:by}\:2\quad \:60=30\cdot \:2$

$=2\cdot \:30$

$30\:\mathrm{divides\:by}\:2\quad \:30=15\cdot \:2$

$=2\cdot \:2\cdot \:15$

$15\:\mathrm{divides\:by}\:3\quad \:15=5\cdot \:3$

$=2\cdot \:2\cdot \:3\cdot \:5$

$2,\:3,\:5\mathrm{\:are\:all\:prime\:numbers,\:therefore\:no\:further\:factorization\:is\:possible}$

$=2\cdot \:2\cdot \:3\cdot \:5$

$=2^2\cdot \:3\cdot \:5$

$=\sqrt{2^2\cdot \:3\cdot \:5}$

Apply Radical Rule:

$=\sqrt{2^2}\sqrt{3\cdot \:5}$

Apply Radical Rule:

$\sqrt{2^2}=2$

$=2\sqrt{3\cdot \:5}$

$\mathrm{Refine}$

$=2\sqrt{15}$

$x_{1,\:2}=\frac{-\left(-10\right)\pm \:2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Separate\:the\:solutions}$

$x_1=\frac{-\left(-10\right)+2\sqrt{15}}{2\cdot \:2},\:x_2=\frac{-\left(-10\right)-2\sqrt{15}}{2\cdot \:2}$

$\frac{-\left(-10\right)+2\sqrt{15}}{2\cdot \:2}$

Apply Rule -(-a)=a

$=\frac{10+2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Multiply\:the\:numbers:}\:2\cdot \:2=4$

$=\frac{10+2\sqrt{15}}{4}$

$=\frac{2\left(5+\sqrt{15}\right)}{4}$

$\mathrm{Cancel\:the\:common\:factor:}\:2$

$=\frac{5+\sqrt{15}}{2}$

$\frac{-\left(-10\right)-2\sqrt{15}}{2\cdot \:2}$

$=\frac{10-2\sqrt{15}}{2\cdot \:2}$

$\mathrm{Multiply\:the\:numbers:}\:2\cdot \:2=4$

$=\frac{10-2\sqrt{15}}{4}$

$=\frac{2\left(5-\sqrt{15}\right)}{4}$

$\mathrm{Cancel\:the\:common\:factor:}\:2$

$=\frac{5-\sqrt{15}}{2}$

$\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}$

$x=\frac{5+\sqrt{15}}{2},\:x=\frac{5-\sqrt{15}}{2}$

8 0

3 years ago

What is the coefficient of x^4y^4 in the expansion (x+y)^8?

Ivanshal [37]

Answer:

C. 70

Step-by-step explanation:

In the expansion of (a + b)^n, the k-th term is ...

nCk·a^(n-k)b^k . . . . . k = 0 to n; nCk = n!/(k!(n-k)!)

Here, we have n=8, k=4, so the term of interest is ...

8C4·x^4y^4 = (8·7·6·5)/(4·3·2·1)x^4y^4 = 70x^4y^4

The coefficient of the term is 70.

3 0

3 years ago

Question 2 (Essay Worth 10 points)

sashaice [31]

Ryan is correct, the mean is about 8.1.

To find the mean, you have to add up all the values, then divide by the total amount.

For Sample A:
60 x 6 + 90 x 7 + 145 x 8 + 150 x 9 + 55 x 10 = 4050

If you add up all the adults, you have 500.

Dividing 4050 by 500 = 8.1

Sample B will produce a very similar result.

5 0

3 years ago

Question 1

r-ruslan [8.4K]

The perimeter of the a and BC is 14 unitsBecause if you add all of the sides together you get 14 and I need points

6 0

3 years ago

Giving brainliest! Can anyone answer this question for me?

Marysya12 [62]

Answer:

1/2

Step-by-step explanation:

7 0

3 years ago

-42/7￼ what is the answer

-42/7 what is the answer