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4 years ago

G 1) a2 + 3a – 40 = 0 . solving quadratic equations

Mathematics

1 answer:

QveST [7]4 years ago

5 0

Answer:

The solution set is {-8, 5}.

Step-by-step explanation:

a^2 + 3a – 40 = 0 .

We need 2 numbers whose product is -40 and whose sum is +3.

They would be + 8 and - 5, so we have the factors:

(a + 8)(a - 5) = 0

Now either a + 8 = 0 or a - 5 = 0, so:

a = -8 or 5.

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mr Goodwill [35]

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4 years ago

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Mr light foot can run 3 miles in half an hour how many minutes will it take him to run 2 miles

Ray Of Light [21]

Answer:

20 minutes

Step-by-step explanation:

3 miles in half an hour(30 minutes) mean Mr. Light runs at an average speed of 1 mile per 10 minutes. To run 2 miles, he would take 20 minutes.

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3 years ago

Solve the system by elimination.<br> -6x + y = 0<br> 9x - 8y = 4

mixas84 [53]

Answer:

(4, 4 )

Step-by-step explanation:

Given the 2 equations

- 6x + 6y = 0 → (1)

9x - 8y = 4 → (2)

Multiplying (1) by 3 and (2) by 2 and adding will eliminate the x- term, that is

- 18x + 18y = 0 → (3)

18x - 16y = 8 → (4)

Add (3) and (4) term by term to eliminate x, then

2y = 8 ( divide both sides by 2 )

y = 4

substitute y = 4 into either of the 2 equations and solve for x

Substituting into (2)

9x - 8(4) = 4

9x - 32 = 4 ( add 32 to both sides )

9x = 36 ( divide both sides by 9 )

x = 4

Solution is (4, 4 )

3 0

3 years ago

What is an equation of the line that passes through the points (-3, 7) and (3, 3)?

Margarita [4]

Answer:

$y = -\frac{2}{3}x + 5$

Step-by-step explanation:

First you have to find the slope

$m = \frac{7 - 3}{-3 - 3} = \frac{4}{-6} = -\frac{2}{3}$

Now use the point-slope form by using one of the points and the slope. Let's use the point (3, 3)

$y - 3 = -\frac{2}{3} (x - 3)$

Multiply thru the equation by 3 to remove the fraction

3y - 9 = -2(x - 3) =

3y - 9 = -2x +6

3y = -2x + 15

$y = -\frac{2}{3}x + 5$ is the equation in slope-intercept form

3 0

3 years ago

In Exercise 13, solve y=f(x) for x. Then find the input when the output is 2.

andrezito [222]

Answer:

x = ±(√y)/3

x = ±(√2)/3

Step-by-step explanation:

Put the given information in the given equation and solve for x:

f(x) = 2

2 = 9x^2 . . . . . use 2 in place of f(x)

2/9 = x^2 . . . . divide by 9

±√(2/9) = x . . . take the square root

x = ±(√2)/3 . . . simplify

_____

Using this as an example, we can solve f(x) = y in the same way:

y = 9x^2 . . . . use y for f(x)

y/9 = x^2 . . . divide by the coefficient of x^2

±√(y/9) = x . . . take the square root; next, simplify

x = ±(√y)/3 . . . . the equation solved for x. Note this matches the above when y=2.

6 0

3 years ago