Question

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7√2-3√8+4√18=
(√90-√40)×√10=
(3√5-2)²=
(7√2-3√3)×(7√2+3√3)=

Answer 1

1)7√2-3√8+4√18=7√2-3√2*4+4√2*9=7√2-6√2+12√2=13√2
2)(√90-√40)*√10=(√10*9 -√10*4)*√10=(3√10 -2√10)*√10=√10*√10=√10^2=10
4)(7√2-3√3)^2