History: The truman doctrine stated that the united states would support greece and turkey with economic and military aid to prevent the spread of communism. this doctrine became the basis for a. the united states foreign policy during the cold war. b. the united states foreign policy of ignoring the soviet union. c. the establishment of the united nations policy of appeasement. d. the creation of the united nations policy of armed involvement.

The truman doctrine stated that the united states

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07.05.2021

Option B. -1.5x-3.5y=-31.5

Solution:

Equation of the lane passing through A and B: -7x+3y=-21.5

If we isolate y, and express the equation in the slope-intercept form y=mx+b, the coefficient of the variable "x" is the slope of this line:

Adding 7x both sides of the equation:

-7x+3y+7x=-21.5+7x

3y=7x-21.5

Dividing both sides of the equation by 3:

(3/3)y=(7/3)x-21.5/3

y=(7/3)x-21.5/3

The slope of this line is m1=7/3 (coefficient of variable x)

This line is perpendicular to the central line PQ, then the product of their slopes must be equal to -1.

Slope of AB: m1=7/3

Slope of PQ: m2

m1 m2 = -1

Replacing m1=7/3

(7/3) m2 = -1

Solving for m2: Multiplying both sides of the equation by 3/4:

(3/7)(7/3) m2 = (3/7)(-1)

m2 = - 3/7

According with the graph we know that the line PQ passes through the point P=(7,6)=(xp, yp)→xp=7, yp=6

Then, using the point-slope equation:

y-y1=m(x-x1); y1=yp=6, m=m2=-3/7, x1=xp=7

Replacing the values:

y-6=(-3/7)(x-7)

Multiplying both sides of the equation by 7:

7(y-6)=7(-3/7)(x-7)

7y-42=(-3)(x-7)

7y-42=-3x+21

Subtracting 7y and 21 both sides of the equation:

7y-42-7y-21=-3x+21-7y-21

-63=-3x-7y

-3x-7y=-63

Dividing all the terms by 2:

-(3/2)x-(7/2)y=-63/2

-1.5x-3.5y=-31.5

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