Evaluate the product ((2 vec{a}+5 vec{b}).(4 vec{a}-5 vec{b}) ).

1.	Evaluate the product ((2 vec{a}+5 vec{b}).(4 vec{a}-5 vec{b}) ).
A.	(\| vec{a}\|^2+2 vec{a}. vec{b}-15\| vec{b}\|^2 )
B.	(8\| vec{a}\|^2+2 vec{a}. vec{b}-15\| vec{b}\|^2 )
C.	(8\| vec{a}\|^2-4 vec{a}. vec{b}-15\| vec{b}\|^2 )
D.	(\| vec{a}\|^2+ vec{a}. vec{b}-5\| vec{b}\|^2 )
Answer» C. (8\| vec{a}\|^2-4 vec{a}. vec{b}-15\| vec{b}\|^2 )

Discussion

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