**Step-by-step explanation:**

Let "c" be the original number of classrooms.

The 1200/c was the original number of students per classroom.

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Equation:

1200/(c-4) = (1200/c)+10

Multiply thru by c(c-4)

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1200c = 1200(c-4)+10c(c-4)

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1200c = 1200c-4800 + 10c^2-40c

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10c^2-40c-4800 = 0

c^2-4c-480 = 0

Factor:

(c-24)(c+20) = 0

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Positive solution:

c = 24 (# of classrooms originaly planned)

**Answer:**

no solution

**Step-by-step explanation:**

**Answer:**

An irrational number is a number that can not be written as the quotient of two integer numbers.

Then if we have:

A = a rational number

B = a irrational number.

Then we can write:

A = x/y

Then the product of A and B can be written as:

A*B = (x/y)*B

Now, let's assume that this product is a rational number, then the product can be written as the quotient between two integer numbers.

(x/y)*B = (m/n)

If we isolate B, we get:

B = (m/n)*(y/x)

We can rewrite this as:

B = (m*y)/(n*x)

Where m, n, y, and x are integer numbers, then:

m*y is an integer

n*x is an integer.

Then B can be written as the quotient of two integer numbers, but this contradicts the initial hypothesis where we assumed that B was an irrational number.

Then the product of an irrational number and a rational number different than zero is always an irrational number.

We need to add the fact that the rational number is different than zero because if:

B is an irrational number

And we multiply it by zero, we get:

B*0 = 0

Then the product of an irrational number and zero is zero, which is a rational number.

**Answer:**

This would be neither as they're passing through points that are across from each other by a large distance.

**Answer:**

5x + 4y = - 8

**Step-by-step explanation:**

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Given

4x - 5y = 20 ( subtract 4x from both sides )

- 5y = - 4x + 20 ( divide all terms by - 5 )

y = x - 4 ← in slope- intercept form

with slope m =

Given a line with slope m then the slope of a line perpendicular to it is

= - = - = - , thus

y = - x + c ← is the partial equation

To find c substitute (- 4, 3) into the partial equation

3 = 5 + c ⇒ c = 3 - 5 = - 2

y = - x - 2 ← in slope- intercept form

Multiply through by 4

4y = - 5x - 8 ( add 5x to both sides )

5x + 4y = - 8 ← equation in standard form