Question 344389
Use the FOIL method,
{{{(5sqrt(9) - 5sqrt(3))(5sqrt(8) + 5sqrt(27))=25sqrt(9*8)+25sqrt(9*27)-25sqrt(3*8)- 25sqrt(3*27)}}}
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{{{(5sqrt(9) - 5sqrt(3))(5sqrt(8) + 5sqrt(27))=25(sqrt(36*2)+sqrt(81*3)-sqrt(6*4)- sqrt(81)))}}}
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{{{(5sqrt(9) - 5sqrt(3))(5sqrt(8) + 5sqrt(27))=25(6sqrt(2)+9sqrt(3)-2sqrt(6)- 9)}}}