I need help with this math question

Question

it’s length is 5in. More then it’s width. If the length were doubled and if the width were decreased by 1 in. The area would be increased by 260 in^2. What are the length and the width of the screen ?

Answer 1

L=5+w

2L(w-1) =A+260

2(5+w)(w-1)= A+260

(10+2w)(w-1) = A+260

Lw = A

(5+w)w = A

2w^2 +8w -10 - (5+w)w = A+260-A

w^2+3w -270 = 0

w=-3/2 +.5sqr1089

= -1.5+16.5

= 15 inches wide

L = 20 inches Long

A=Lw=20(15)= 300 in^2

+260=560

new A = 40(14)= 560