The value of (a - b - c)(a - b + c) is:
a2 + b2 + c2 + 2ab
a2 + b2 - c2 - 2ab
a2 + b2 + c2 - 2ab
a2 + b2 - c2 + 2ab
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(a - b - c)(a - b + c)
= a (a - b + c) - b (a - b + c) - c (a - b + c)
= a(1+1) - ab + ac - ab + b(1+1) - bc -ac + bc - c(1+1)
= a2 + (- ab - ab) + (ac -ac) + b2 + (- bc + bc) - c2
= a2 - 2ab + b2 - c2
Hence, option 2 is the correct option.
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(3x - 4y)2 - (3x + 4y)2 is equal to:
18x2 + 32y2
18x2 - 32y2
-48xy
48xy
The value of (0.8)2 - 0.32 + (0.2)2 is equal to:
1
3.6
0.36
0.036
Use direct method to evaluate the following product:
(a - 8) (a + 2)
(b - 3) (b - 5)