SOLUTION: I need help with this question: {{{ (5sqrt(30)-7sqrt(70))(4sqrt(42)-3sqrt(105)) }}} If you could give a explanation with steps would be appreciated!

Algebra ->  Radicals -> SOLUTION: I need help with this question: {{{ (5sqrt(30)-7sqrt(70))(4sqrt(42)-3sqrt(105)) }}} If you could give a explanation with steps would be appreciated!      Log On


   

Question 873460: I need help with this question: +%285sqrt%2830%29-7sqrt%2870%29%29%284sqrt%2842%29-3sqrt%28105%29%29+
If you could give a explanation with steps would be appreciated!
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
FOIL Method:
First:+%285%2Asqrt%2830%29%29%284%2Asqrt%2842%29%29=20%2Asqrt%281260%29=120%2Asqrt%2835%29
Outer:+%285%2Asqrt%2830%29%29%28-3%2Asqrt%28105%29%29=-15%2Asqrt%283150%29=-225%2Asqrt%2814%29
Inner:+%28-7%2Asqrt%2870%29%29%284%2Asqrt%2842%29%29=-28%2Asqrt%282940%29=-392%2Asqrt%2815%29
Last:+%28-7%2Asqrt%2870%29%29%28-3%2Asqrt%28105%29%29=21%2Asqrt%287350%29=735%2Asqrt%286%29
Add it up.
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