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Question -

Find the value of x if the area of тИЖ is 35 square cms with vertices (x,4), (2, -6) and (5, 4).



Answer -

Given (x, 4), (2, -6)and (5, 4) are the vertices of a triangle.

We have the conditionthat three points to be collinear, the area of the triangle formed by thesepoints will be zero. Now, we know that, vertices of a triangle are (x1,y1), (x2, y2) and (x3, y3),then the area of the triangle is given by,

тЗТ┬а[x (тАУ 10) тАУ 4(тАУ3) + 1(8 тАУ 30)] = ┬▒ 70

тЗТ┬а[тАУ 10x + 12 +38] = ┬▒ 70

тЗТ┬а┬▒70 = тАУ 10x + 50

Taking positive sign,we get

тЗТ┬а+ 70 = тАУ 10x +50

тЗТ┬а10x = тАУ 20

тЗТ┬аx = тАУ 2

Taking тАУnegative sign,we get

тЗТ┬атАУ 70 = тАУ 10x +50

тЗТ┬а10x = 120

тЗТ┬аx = 12

Thus x = тАУ 2, 12

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