Đáp án:
Giải thích các bước giải:
Bài 1:
A(x)=3x^4-3/4 x^3 + 2x^2-3
B(x)=8x^4 + 1/5 x^3 -9x+2/5
A(x) + B(x)= (3x^4 - 3/4x^3 + 2x^2-3) + (8x^4 + 1/5 x^3 - 9x+2/5)
A(x) +B(x)=(3x^4 + 8x ^4) + (-3/4 x^3 + 1/5 x^3) + 2x^2 - 9x + (-3 + 2/5)
A(x) +B(x)= 11 x^4 - (-11/20 x^3) + 2x^2 - 9x - 13/5
A(x) - B(x) = (3x^4 - 3/4x^3 + 2x^2-3) - (8x^4 - 1/5 x^3 + 9x - 2/5)
A(x) - B(x)= (3x^4 - 8x^4) + (-3/4 x^3 -1/5x^3) + 2x^2 + 9x + (-3 - 2/5)
A(x)- B(x)= -5x^4 - 19/20 + 2x^2 + 9x - 17/5
B(x) - A(x)=(8x^4 + 1/5 x^3 - 9x + 2/5) - (3x^4 + 3/4x^3-2x^2 + 3)
B(x)-A(x) = (8x^4 - 3x^4) + (1/5x^3 + 3/4x^3) - 2x^2 -9x+(2/5+3)
B(x) - A(x)=5x^4 + 19/20 x^3 - 2x^2 -9x + 17/5
Bài 2:
a.P(x)=5x^5-4x^4-2x^3+4x^2 +3x+6
Q(x)=-x^5 +2x^4 -2x^3 +3x^2-x
b.P(x) - Q(x)=(5x^5+3x-4x^4-2x^3+6+4x^2) - (2x^4 +x -3x^2 +2x^3 -1/4 +x^3)
P(x)-Q(x)=5x^5 + (3x+x) + (-4x^4-2x^4) + (-2x^3+2x^3) + (6-1/4) + (4x^2-3x^2)
P(x)-Q(x)=5x^5 +4x -6x^4 +23/4 +x^2
P(x)+Q(x)=(5x^5+3x-4x^4-2x^3+6+4x^2) + (2x^4-x+3x^2-2x^3+1/4-x^5)
P(x)+Q(x)= (5x^5-x^5) + (3x-x)+ (-4x^4+2x^4) +(-2x^3-2x^3) + (6+1/4) +(4x^2+3x^2)
P(x)+Q(x)=4x^5 +2x -2x^4 -4x^3 +25/4 +7x^2
Bài 3:
A(x)+B(x)=(3x^4-3/4x^3+2x^2-3) + (8x^4+1/5x^3-9x+2/5)
A(x)+B(x)=(3x^4+8x^4)+(-3/4x^3+1/5x^3)+2x^2-9x+(-3+2/5)
A(x)+B(x)=11 x^4 -11x^3 +2x^2-9x -13/5
A(x)- B(x)= (3x^4-3/4x^3+2x^2-3)-(8x^4-1/5x^3+9x-2/5)
A(x)-B(x)=(3x^4-8x^4)+(-3/4x^3-1/5x^3)+2x^2-9x+(-3)-2/5)
A(x)-B(x)=-5x^4 -19/20x^3 +2x^2 -9x -17/5
