Prove that : (a+b)(c+d)=ac+ad+bc+bd I'd be very greatful
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(a+b)(c+d)=(a+b)c+(a+b)d=ac+bc+ad+bd
Originally Posted by alternative Prove that : (a+b)(c+d)=ac+ad+bc+bd I'd be very greatful See attachment - I think it's pretty obvious that the area of the large rectangle (outlined in black) equals the sum of the areas of all the smaller rectangles. Therefore $\displaystyle (a + b)(c + d) = ac + ad + bc + bd$.
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