Đáp án:
Giải thích các bước giải:
a) A(x)=-x+x²+3x+4x³-6x²+2x^4-7
=(-x+3x)+(x²-6x²)+4x³+2x^4-7
=2x-5x²+4x³+2x^4-7
B(x)=x^4-2x²+x³-3x-x²+4x³-8+6x
=(-2x²-x²)+(x³+4x³)+(-3x+6x)+x^4-8
=-3x²+5x³+3x+x^4-8
Sắp xếp:
A=2x^4+4x³-5x²+2x-7
B=x^4+5x³-3x²+3x-8
b) C1: A(x)+B(x)=(2x^4+4x³-5x²+2x-7)+(x^4+5x³-3x²+3x-8)
=2x^4+4x³-5x²+2x-7+x^4+5x³-3x²+3x-8
=(2x^4+x^4)+(4x³+5x³)+(-5x²-3x²)+(2x+3x)+(-7-8)
=3x^4+9x³-8x²+5x-15
A(x)-B(x)=(2x^4+4x³-5x²+2x-7)-(x^4+5x³-3x²+3x-8)
=2x^4+4x³-5x²+2x-7-x^4-5x³+3x²-3x+8
=(2x^4-x^4)+(4x³-5x³)+(-5x²+3x²)+(2x-3x)+(-7+8)
=x^4-x³-2x²-x-1
B(x)-A(x)=(x^4+5x³-3x²+3x-8)-(2x^4+4x³-5x²+2x-7)
=x^4+5x³-3x²+3x-8-2x^4-4x³+5x²-2x+7
=(x^4-2x^4)+(5x³-4x³)+(-3x²+5x²)+(3x-2x)+(-8+7)
=-x^4+x³+2x²+x-1
C2: A(x)=2x^4+4x³-5x²+2x-7
+
B(x)= x^4 +5x³-3x²+3x-8
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A(x)+B(x)=3x^4+9x³-8x²+5x-15
A(x)=2x^4+4x³-5x²+2x-7
-
B(x)=x^4+5x³-3x²+3x-8
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A(x)-B(x)=x^4 - x³- 2x² - x - 1
B(x)=x^4+5x³-3x²+3x-8
-
A(x)=2x^4+4x³-5x²+2x-7
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B(x)-A(x)=-x^4+ x³+2x²+ x- 1
Chúc bạn học tốt xin ctlhn và 5* ạ^^
