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3 years ago

Solve the system of linear equations using linear combination.

Mathematics

2 answers:

lisov135 [29]3 years ago

8 0

Answer:

The answer is (1,7). Hope it helps

brilliants [131]3 years ago

6 0

3a + 6b = 45
2a - 2b = -12....multiply by 3
----------------
3a + 6b = 45
6a - 6b = - 36 ...(result of multiplying by 3)
---------------add
9a = 9
a = 1

3a + 6b = 45
3(1) + 6b = 45
3 + 6b = 45
6b = 45 - 3
6b = 42
b = 7

solution is : (1,7)

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Find the sum of the squares of the roots of 3x^2 + 4x + 12 = 0

Contact [7]

Answer:

-56/9

Step-by-step explanation:

Let p and q be the roots of the equation.

So, here's how we're gonna work it out:

${p}^{2} + {q}^{2} = \\ {p}^{2} + {q}^{2} +2 pq - 2pq = \\ ( {p}^{2} +2pq + {q}^{2}) - 2pq = \\ {(p + q)}^{2} - 2pq$

Vieta's formulas give us the sum and the product of the roots of a quadratic equation. Using them we obtain:

p + q = -b / a = - 4 / 3
p × q = c / a = 12 / 3 = 4

${(p + q)}^{2} - 2pq = \\ {( - \frac{ 4}{3} )}^{2} - 2 \times 4 = \frac{16}{9 } - 8 = \\ \frac{16 - 72}{9} = - \frac{56}{9}$

4 0

3 years ago

Solve for x in the given interval. sec x= -2√3/3, for π/2 ≤x≤π

drek231 [11]

Answer:

b. $x=\frac{5\pi}{6}$

Step-by-step explanation:

The given function is

$\sec x=-\frac{2\sqrt{3} }{3},\:\:for\:\:\frac{\pi}{2}\le x \le \pi$

Recall that the reciprocal of the cosine ratio is the secant ratio.

This implies that;

$\frac{1}{\cos x}=-\frac{2\sqrt{3} }{3}$

$\Rightarrow \cos x=-\frac{3}{2\sqrt{3} }$

$\Rightarrow \cos x=-\frac{\sqrt{3}}{2}$

We take the inverse cosine of both sides to obtain;

$x=\cos^{-1}(-\frac{\sqrt{3}}{2})$

$x=\frac{5\pi}{6}$

4 0

3 years ago

A national grocery store chain wants to test the difference in the average weight of turkeys sold in Detroit and the average wei

Arte-miy333 [17]

Answer:

Calculated value t = 1.3622 < 2.081 at 0.05 level of significance with 42 degrees of freedom

The null hypothesis is accepted .

Assume the population variances are approximately the same

Step-by-step explanation:

Explanation:-

Given data a random sample of 20 turkeys sold at the chain's stores in Detroit yielded a sample mean of 17.53 pounds, with a sample standard deviation of 3.2 pounds

The first sample size 'n₁'= 20

mean of the first sample 'x₁⁻'= 17.53 pounds

standard deviation of first sample S₁ = 3.2 pounds

Given data a random sample of 24 turkeys sold at the chain's stores in Charlotte yielded a sample mean of 14.89 pounds, with a sample standard deviation of 2.7 pounds

The second sample size n₂ = 24

mean of the second sample "x₂⁻"= 14.89 pounds

standard deviation of second sample S₂ = 2.7 pounds

Null hypothesis:-H₀: The Population Variance are approximately same

Alternatively hypothesis: H₁:The Population Variance are approximately same

Level of significance ∝ =0.05

Degrees of freedom ν = n₁ +n₂ -2 =20+24-2 = 42

Test statistic :-

$t = \frac{x^{-} _{1} - x_{2} }{\sqrt{S^2(\frac{1}{n_{1} } }+\frac{1}{n_{2} } }$

where $S^{2} = \frac{n_{1} S_{1} ^{2}+n_{2}S_{2} ^{2} }{n_{1} +n_{2} -2}$

$S^{2} = \frac{20X(3.2)^2+24X(2.7)^2}{20+24-2}$

substitute values and we get S² = 40.988

$t= \frac{17.53-14.89 }{\sqrt{40.988(\frac{1}{20} }+\frac{1}{24} )}$

t = 1.3622

Calculated value t = 1.3622

Tabulated value 't' = 2.081

Calculated value t = 1.3622 < 2.081 at 0.05 level of significance with 42 degrees of freedom

Conclusion:-

The null hypothesis is accepted

Assume the population variances are approximately the same.

6 0

2 years ago

Which set of reflections would carry rectangle ABCD onto itself?

Whitepunk [10]

Answer:

i think that the answer would be but im not 100% sure

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

two angles are supplementary of the sum is 180. the larger angle measures four degrees more than sevem times the measure of a sm

Aleksandr [31]

Answer:

22 and 158

Step-by-step explanation:

Supplementary angles add to 180. This is means there is a small and large angle. Adding together, they make 180.

"the larger angle measures four degrees more than seven times the measure of a smaller angle" is represented as 7x+4.
"x represents the measure of the smaller angle" is represented as x.

x + 7x+4 =180

8x+4=180

8x=176

x= 22

This is the measure of the smaller angle. The larger angle is 7(22)+4 = 158

5 0

3 years ago