Prove that (2x−3y)(2x+3y)=(2x)2−(3y)2 geometrically.
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Solution
Step 1: Draw a square and cut into 3 parts. Step 2: There are 1 hided square green and 2 rectangles (pink, blue) Step 3: Area of the full square =(2x)2−(3y)2 Step 4: Now we have to find the area of rectangle as shown in the figure. Step 5: Consider the area of pink rectangle = length × breadth =2x(2x−3y) Step 6: Area of blue rectangle =3y(2x−3y) Step 7: Area of full square = area of pink rectangle + area of blue rectangle. i.e., (2x)2−(3y)2=2x(2x−3y)+3y(2x−3y) (2x)2−(3y)2=(2x+3y)(2x−3y) Hence, geometrically we proved the identity (2x)2−(3y)2=(2x+3y)(2x−3y).