Question

Solving a word problem using a quadratic equation with rationa...

Answer 1

Answer:

length : 8 m

width : 13/2 = 6.5 m

Step-by-step explanation:

area of rectangle = l(ength)×w(idth) = 52

l = 2w - 5

=> (2w - 5)×w = 52

=> 2w² -5w - 52 = 0

we know, when transforming this quadratic equation into a multiplication of two expressions of w, that we need to have 2w and w (to make 2w²), and then which 2 numbers multiply to 52 and add to -5 (when one is multiplied by 2 due to 2w) : -13 and 4

=> (2w - 13)×(w + 4) = 0

=> 2 solutions for w :

2w-13 = 0

2w = 13, w = 13/2

w+4 = 0, w = -4

negative values for a side length of a shape do not make sense, so the only usable solution is w = 13/2

=> l = 2w - 5 = 13 - 5 = 8