Answer:
l=35 inches
w= 9 inches
Explanation:
Area is 315 square inches
Area=l*w=315 (Equation 1)
l=4w-1 (Equation 2)
Putting value of l from equation 2 in equation 1
(4w-1)w=315
4w^2-w-315=0
Solving by using quadratic equation
a=4, b=-1, c=-315
w= (-b+sqrt(b^2-4ac))/2a and w= (-b-sqrt(b^2-4ac))/2a
w= (1+sqrt(1+5040))/8 and w= (1-sqrt(1+5040))/8
w= (1+sqrt(5041))/8 and w= (1-sqrt(5041))/8
sqrt(5041)=71
w= (1+71)/8 and w= (1-71)/8
w=72/8 and w=-70/8
as width can't be a negative number so we'll solve for w=72/8=9
width =9 inches
putting w in equation 2
l=(4*9)-1
l=35 inches