Answer:
23mm
528 mm^2
Step-by-step explanation:
The area of a rectangle is given as the product of its length and width.
Given that 12x²+17x-5mm² is the area
factorize
12x²+17x-5 = 12x²+20x -3x-5
= 4x(3x+5)-1(3x+5)
= (3x+5)(4x-1)
For the rectangle to be a square, it means that the sides 3x+ 5 and 4x - 1 are equal. Hence
3x + 5 = 4x -1
collect like terms
3x - 4x = -5 -1
-x = -6
x = 6
substitute into the sides
3x + 5 = 3(6) + 5 = 23
4x -1 = 4(6) - 1 = 23
The area of the square which is a product of the sides
= 23 * 23
= 529
