Answer:
width of the border is 3 inches
Step-by-step explanation:
Given data
size = 8 inches by 10 inches
area = 144 square inches
to find out
width of the border
solution
first we consider width of border is x
area of new full rectangle = (8 + 2x ) × ( 10 + 2x )
so we know area of photo = 8 × 10 = 80 square inches
and area of border = 144 square inches that is given
so new area of photo with the border is 80 + 144 = 224 square inches
and we can say that
area of full rectangle - area of the photograph = Area of Border
(8 + 2x) × (10 + 2x) – (80) = 144 square inches
80 + 16x + 20x + – 80 = 144
+ 36x – 144 = 0
solve thios equation we get
+ 9x – 36 = 0
solve thios equation we get
(x + 12) (x – 3) = 0
so here x have two value one is negative and other is positive
so we consider only positive value
x = -12 or x = 3
width of the border is 3 inches
