Question

The area of a rectangular playing field is 192square meters. The length of the field is x+12 and the width is x-4. How do you calculate x by using quadratic formula?

Answer 1

Area of rectangular Field = length *width;

192 sq.m = (x+12)*(x-4);

192 = x2+8x-48;

0 = x2+8x-240;

Now solving this equation and find the value of x;

0 = x2-12x+20x-240;

0 = x(x-12)+20(x-12);

0 = (x-12)(x+20);

x = 12 and x = -20;

Now considering positive value of x ;

so length = x+12 = 24;

width = x-4 = 8