Answer:
x = ± 
Step-by-step explanation:
Given
y = x² + 11 ( subtract 11 from both sides )
y - 11 = x² ( take the square root of both sides )
± = 
, hence
x = ±
Let the width be X
Then the length is X + 70
The perimeter is the sum of all sides
There are 2 widths (left side and right side) and 2 lengths (top and bottom)
Perimeter = 2 * width + 2 * length
Perimeter = 2 * X + 2 * (X+70)
Perimeter: 2 X + 2 X + 140 = 380
4 X = 380-140
4 X = 240
X = 240 / 4
X = 60
Width = 60 - the smaller of two sides
Length = X + 70 = 60 + 70 = 130 - the larger of two sides
Check:
<span>
2 * 60 + 2 * 130 = 380 </span>
Initial cost = $126
Final cost = $150
Then
Amount of change = (150 - 126) dollars
= 24 dollars
Then
Percentage change = (24/126) * 100
= 2400/126 percent
= 19.05 percent
So from the above deduction we can easily conclude that the percentage change is 19.05%. I hope the procedure is simple enough for you to easily understand. You can generally use this method for solving similar kind of problems in future without requiring any kind of help from outside.
