Answer:
6 inches by 6 inches
Explanation:
Area of the square = 256 inches ²
Given equation:
(x + 10)² = 256
Where,
x = side measure of the original square
(x + 10)² = 256
(x + 10)(x + 10) = 256
x² + 10x + 10x + 100 = 256
x² + 20x + 100 = 256
x² + 20x + 100 - 256 = 0
x² + 20x - 156 = 0
Solve the quadratic equation by factorization
Find two numbers whose product is -156 and sum is 20
The numbers are -26 and 6
x² + 26x - 6x - 156 = 0
x(x + 26) - 6(x + 26) = 0
(x + 26) (x - 6) = 0
x + 26 = 0 or x - 6 = 0
x = -26 or x = 6
Side length of a square can not be negative
Therefore,
x = 6 inches
6 inches by 6 inches