Question

pq is a straight line of 13 units length if p has coordinates (2,5) and q has the co- ordinates (x,-7) ,then the value of x is ?

Answer 1

PQ = 13

Apply distance formula

PQ = √(X2-X1)² + (Y2-Y1)²

squaring both sides

PQ² = (X2-X1)² + (Y2-Y1)²

(13)² = (x - 2)² + (-7 - 5 )²

169 = x²+4-4x + 144

x²+4-4x+144-169 = 0

x² -4x -21 = 0

x²-7x+3x-21 = 0

x(x-7)+3(x-7) = 0

(x-7)(x+3) = 0

x = 7. OR. x = -3