Answer:
Explanation:
w=l-1
∵A=l×w
∴A=l×(l-1)
⇒42=l²-l
⇒l²-l-42=0 (After subtracting 42 from both sides)
Two factors of 42 that add to give negative 1 :-7+6
∴ (l-7)(l+6)=0
∴ l=7 or l=-6
but remember that length is a scalar quantity, hence l≠6 but l=7.
I hope this helped you solve this math problem and made you better understand