Question 579849
let side of square be x
area = l*w= x^2

3 is added to its side

Area of this square = (x+3)^2

x^2+(x+3)^2= 617 
x^2+x^2+6x+9=617
2x^2+6x-617+9=0
2x^2+6x-608=0
/2
x^2+3x-304 =0

x^2+19x-16x-304=0

x(x+19)-16(x+19)=0
(x+19)(x-16)=0

x=-19 OR 16

ignore negative

the length of side = 16cm