Toán Lớp 9: ( √125- √12-2√5)(3√5- √3+ √27)
help me !
rút gọn biểu thức!!!!!!!!!!!!!
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Toán Lớp 9: ( √125- √12-2√5)(3√5- √3+ √27)
help me !
rút gọn biểu thức!!!!!!!!!!!!!
Comments ( 1 )
=(sqrt{25·5} -sqrt{4·3} -2sqrt5)(3sqrt5 -sqrt3 +sqrt{9·3})
=(sqrt{5^2·5} -sqrt{2^2·3} -2sqrt5)(3sqrt5 -sqrt3 +sqrt{3^2·3})
=(5sqrt5 -2sqrt3 -2sqrt5)(3sqrt5 -sqrt3 +3sqrt3)
=(3sqrt5 -2sqrt3)(3sqrt5 +2sqrt3)
=(3sqrt5)^2-(2sqrt3)^2
=45-12
=33