So sánh P và Q biết :
\(P=a+\left\{\left(a-3\right)-\left[\left(a+3\right)-\left(-a-2\right)\right]\right\}\)
\(Q=\left[a+\left(a+3\right)\right]-\left[\left(a+2\right)-\left(a-2\right)\right]\)
Giúp mình nha <3
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\(P=a-\left\{\left(a-3\right)-\left[\left(a-3\right)-\left(-a-2\right)\right]\right\}\\ =a-\left(a-3\right)+\left[\left(a-3\right)-\left(-a-2\right)\right]\\ =a-\left(a-3\right)+\left(a-3\right)-\left(-a-2\right)\\ =a-a+3+a-3+a+2\\ =\left(a-a+a+a\right)+\left(3-3+2\right)\\ =2a+2\)
\(Q=\left[a+\left(a+3\right)\right]-\left[\left(a+2\right)-\left(a-2\right)\right]\\ =a+\left(a+3\right)-\left(a+2\right)+\left(a-2\right)\\ =a+a+3-a-2+a-2\\ =\left(a+a-a+a\right)+\left(3-2-2\right)\\ =2a-1\)
Vì \(2a+2>2a-1\) nên \(P>Q\)
Vậy \(P>Q\)
a) \(A=\left(3x+1\right)^2-2\left(3x+1\right)\left(3x+5\right)+\left(5x+5\right)^2\)
\(A=\left[\left(3x+1\right)-\left(5x+5\right)\right]^2\)
\(A=\left(-2x-4\right)^2\)
A = (3x + 1)2 - 2(3x + 1)(5x + 5) + (5x + 5)2
= [(3x + 1)-(5x + 5)]2
= (3x + 1 - 5x - 5)2
= [(-2x) - 4]2
B = (3 + 1)(32 + 1)(34 + 1)(38 + 1)(316 +1)(332 + 1)
=> (3 - 1)B = (3 - 1)(3 + 1)(32 + 1)(34 + 1)(38 + 1)(316 +1)(332 + 1)
=>2B = (32 - 1)(32 + 1)(34 + 1)(38 + 1)(316 +1)(332 + 1)
= (34 - 1)(34 + 1)(38 + 1)(316 +1)(332 + 1)
= (38 - 1)(38 + 1)(316 +1)(332 + 1)
= (316 - 1)316 +1)(332 + 1)
= (332 - 1)(332 + 1)
= 364 - 1
vì 2B = 364 - 1
=> B = \(\dfrac{3^{64}-1}{2}\)
C = a2 + b2 + c2 + 2ab - 2ac - 2bc + a2 + b2 + c2 - 2ab + 2ac - 2bc - 2( b2 - 2bc + c2)
= 2a2 + 2b2 + 2c2 - 4bc - 2b2 + 4bc - 2c2
= 2a2