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3 years ago

Solving by elimination 5x+2y= -3 3x+3y=9 please help me solve x and y

1 answer:

6 0

1) -3(5x+2y=-3)⇒ -15x-6y=9
⇒ -9x=27
2(3x+3y=9)⇒ 6x+6y=18

2) -9x/-9=27/-9 ⇒ x=-3

3) 3(-3)+3y=9⇒ -9+9+3y=9+9⇒ 3y/3=18/3⇒ y=6

Answer: (-3,6)

Reasoning:
Step 1) In order to eliminate, first I had to multiple the first equation by -3 and the second by 2 so that when combining the equations y would cancel each other out so that I could solve for x. <em>Note: There are many combinations as to how you could multiple the equations so that either the x or y would cancel out.
</em>
Step 2) Once y is eliminated, solve for x.

Step 3) Now plug x back into one of the original equations and solve for y. <em>Note: Plug x back into one of the original equations, not the equations that were changed by multiplication,</em>

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Some researchers claim that herbal supplements (such as ginkgo biloba) can impact human memory. To test this claim, a researcher

Alecsey [184]

Answer:

(a) The data are not sufficient to demonstrate that the herb has a significant effect on memory.

(b) Cohen's d = 5.07

Step-by-step explanation:

(a) Null hypothesis: The herbal supplement (ginkgo biloba) can impact human memory

Alternate hypothesis: The herbal supplement (ginkgo biloba) cannot impact human memory.

Z = (sample mean - population mean) ÷ sd/√n

Sample mean = 76, population mean = 70, sd = 15, n = 25

Z = (76 - 70) ÷ 15/√25 = 6 ÷ 3 = 2

Using a 0.05 significance level for a two tailed test, the critical value is 1.96

For a two tailed test, the region of no rejection of the null hypothesis lies between -1.96 and 1.96

Conclusion: Since the test statistic (Z = 2) falls outside the region bounded by -1.96 and 1.96, reject the null hypothesis. The herbal supplement (ginkgo biloba) cannot impact human memory.

Hence, the data are not sufficient to demonstrate that the herb has a significant effect on memory.

(b) Cohen's d = M/sd = 76/15 = 5.07

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3 years ago

What is the greatest common factor of 24 and 64?

Genrish500 [490]

The answer to the problem is 8

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3 years ago

Noah invested $2,500 in an account paying 4.5% simple interest. How much was his account worth after 5 years?

guajiro [1.7K]

Answer:

$3,062.50 after 5 years.

Step-by-step explanation:

The answer is 3,062.50 because 4.5% of 2,500 is 112.5 and 112.5 multiplied by 5 is 562.5 and 2,500 plus 562.5 is 3,062.50.

P.S Can I have brainliest?

8 0

3 years ago

Please help me solve this problem

Karo-lina-s [1.5K]

3.1 a) x = 6 / 5 or x = 2, b) x = - 3 / 2 or x = - 1 / 4, c) x = - 3 or x = 2, d) x = 1 or x = - 2.

3.2 a) x = 9 or x = - 3, b) x = 1 or x = - 1 / 4, c) x = - 3 or x = - 5 d) x = 8 or x = - 18

<h3>How to solve algebraic problems by appying absolute value properties</h3>

In this question we have eight expressions involving <em>absolute value</em> expressions, which can be solved by using the following procedure:

3.1 a) |(1 / 2) · x| = 3 - 2 · x

For x ≥ 0:

(1 / 2) · x = 3 - 2 · x

(5 / 2) · x = 3

x = 6 / 5

For x < 0:

- (1 / 2) · x = 3 - 2 · x

(3 / 2) · x = 3

x = 2

b) |x - 1| = 3 · x + 2

For x ≥ 1:

x - 1 = 3 · x + 2

2 · x = - 3

x = - 3 / 2

For x < 1:

- x + 1 = 3 · x + 2

4 · x = - 1

x = - 1 / 4

c) |5 · x| = x - 12

For x ≥ 0:

5 · x = x - 12

4 · x = - 12

x = - 3

For x < 0:

- 5 · x = x - 12

6 · x = 12

x = 2

d) |7 - x| = 5 · x + 1

For x ≤ 7:

7 - x = 5 · x + 1

6 · x = 6

x = 1

For x > 7:

x - 7 = 5 · x + 1

4 · x = - 8

x = - 2

3.2 a) |9 + x| = 2 · x

For x ≥ - 9:

9 + x = 2 · x

x = 9

For x < 9:

- 9 - x = 2 · x

3 · x = - 9

x = - 3

b) |5 · x| - 3 · x = 2

For x ≥ 0:

|5 · x| = 2 + 3 · x

5 · x = 2 + 3 · x

2 · x = 2

x = 1

For x < 0:

- 5 · x = 2 + 3 · x

- 8 · x = 2

x = - 1 / 4

c) |x + 6| - 9 = 2 · x

For x ≥ - 6:

x + 6 - 9 = 2 · x

x - 3 = 2 · x

x = - 3

For x < - 6:

- x - 6 - 9 = 2 · x

- x - 15 = 2 · x

3 · x = - 15

x = - 5

d) |2 · x - 3| + x = 21

For x ≥ 3 / 2:

2 · x - 3 + x = 21

3 · x = 24

x = 8

For x < 3 / 2:

- 2 · x + 3 + x = 21

- x = 18

x = - 18

To learn more on absolute values: brainly.com/question/1301718

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2 years ago

Tanya says that the product of a multiple of ten and a multiple of ten will always be zero. Is she correct

kondor19780726 [428]

No she is wrong because product of a multiple of ten and a multiple of ten will not always be zero

8 0

3 years ago

Read 2 more answers