Respostas

2014-08-28T13:12:22-03:00
A= 3x²+7x
 B= -4x²+5x-2 
 C=6x+1
A+B=(3x^2+7x)+(-4x^2+5x-2)\\\\=3x^2+7x-4x^2+5x-2\\\\=(3x^2-4x^2)+(7x+5x)+2\\\\A+B=-x^2+12x+2
soma-se sempre x²com x²....x com x
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B-A=(-4x^2+5x-2)-(3x^2+7x)\\\\=-4x^2+5x-2-3x^2-7x\\\\=(-4x^2-3x^2)+(5x-7x)-2\\\\A-B=-7x^2-2x-2
o sinal de negativo na frente do parenteses..faz com que tudo que está dentro do parenteses troque de sinal
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3C+2A =3*(6x+1)+2*(3x^2+7x)\\\\=18x+3 +6x^2+14x\\\\=6x^2+(18x+14x)+4\\\\3C+2A=6x^2+32x+4 ...ou(3x^2+16x+2)
vc pode simplificar dividindo tudo por 2
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A*C=(3x^2+7x)*(6x+1)\\\\=(3x^2*6x)+(3x^2*1)+(7x*6x)+(7x*1)\\\\=18x^3+3x^2+13x+7x\\\\\ A*C=18x^3+3x^2+20x
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C^2-B=(6x+1)^2-(-4x^2+5x-2)\\\\=((6x)^2+[2*6x*1]+1^2)+(4x^2-5x+2)\\\\=(6^2x^2)+[12x]+1)+(4x^2-5x+2)\\\\=36x^2+12x+1+4x^2-5x+2\\\\=(36x^2+4x^2)+(12x-5x)+(1+2)\\\\=40x^2-7x+3

produtos  notaveis
(a+b)^2=a^2+[2*a*b]+b^2
a = primeiro numero
b = segundo numero
1 5 1