The length of the top of a table is 7 m greater than the width. the area is 78 msquared2. find the dimensions of the table.

Let the width = x
      the length = x+7 
 => Area equation = length x width = x(x+7) = x^2 +7x = 78
=> x^2+7x -78 = 0
=> (x-6)(x+13)=0
=> x=6 or x=-13(no)
 => the width = 6 m
=> the length = 6+7= 13 m