SOLUTION: Simplify: (–7 sqrt11 - sqrt7)(sqrt7 – 10sqrt11)

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Question 158204: Simplify: (–7 sqrt11 - sqrt7)(sqrt7 – 10sqrt11)
Found 3 solutions by jim_thompson5910, checkley77, MathLover1:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%28-7%2Asqrt%2811%29-sqrt%287%29%29%28sqrt%287%29-10%2Asqrt%2811%29%29 Start with the given expression.


FOIL


-7%2Asqrt%2877%29%2B70%2Asqrt%28121%29+-sqrt%2849%29+%2B10%2Asqrt%2877%29 Multiply


-7%2Asqrt%2877%29%2B70%2A%2811%29-7%2B10%2Asqrt%2877%29 Take the square root of 121 to get 11. Take the square root of 49 to get 7.


-7%2Asqrt%2877%29%2B770-7%2B10%2Asqrt%2877%29 Multiply


763%2B3%2Asqrt%2877%29 Combine like terms


So


Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
(–7 sqrt11 - sqrt7)(sqrt7 – 10sqrt11)
-7SQRT11-SQRT7
SQRT7-10SQRT11 MULTIPLY
--------------------------------------
-7SQRT77-7+70*11+10SQRT77
3SQRT77-7+770
3SQRT77-763

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
(-7*sqrt%2811%29 –sqrt%287%29)(sqrt%287%29 –10sqrt%2811%29)=
(-7+sqrt%2811%29* sqrt%287%29 + 10sqrt%2811%29* 7+sqrt%2811%29 – sqrt%287%29* sqrt%287%29 + sqrt%287%29* 10sqrt%2811%29)=
(-7+sqrt%2811%2A7%29 + 70sqrt%2811%29%5E2 – sqrt%287%29%5E2 + 10sqrt%2811%2A7%29)=
-7+sqrt%2877%29 + 70%2A11 – 7 + 10%2A77=
–(7*8.78) +770 –7 +770=
–61.46 + 770 –7 + 770=
–68.46+ 1540=
+1471.54