Question

If the distance between two points x,7 and, 1,15 is 10, find the value of X

Answer 1

Distance between two points = √[(x2-x1)^2+(y2-y1)^2]

10 = √[(1-x)^2+(15-7)^2

10 = √(1+x^2-2x+64)

10 = √(x^2-2x+65)

Squaring on both side.

100 = x^2-2x+65

x^2-2x+65-100 = 0

x^2-2x-35 = 0

x^2-7x+5x-35 = 0

x(x-7)+5(x-7) = 0

(x+5)+ (x-7) = 0

x+5 = 0 and x-7 = 0

x = -5 and x = 7

Answer 2

distance formula =√( x2-x1 )² + (y2-y1)²

10 = √ ( 1- x )² + (15-7) ²

10² = (1-x)² + 8²

100-64 = (1-x)²

√36 = 1-x

6 = 1-x

-x = 6-1

x = - 5