Question

Answer 1

a: Khi x=-1 thì

\(A=\left(-3-5-4+8+5\right)\cdot\left(-1\right)=\left(-1\right)\cdot1=-1\)

b: \(B=\dfrac{12x^3+4x^2-2x-4}{-x}\)

Khi x=-1 thì \(B=\dfrac{-12+4+2-4}{1}=-12+2=-10\)

c: \(C=-5y-3x+3x^2-2x^2y^2\)

Khi x=-1 và y=-2 thì 

C=10+3+3-2*(-2)^2

=16-8=8

d: Khi x=-1 và y=-2 thì

\(D=-\left(-3+2+6-12\right)\cdot\left(2\cdot\left(-1\right)\cdot\left(-2\right)\right)\)

=7*4=28

f: \(E=\dfrac{2xy^2-3xy}{-2xy}=-y+\dfrac{3}{2}=2+\dfrac{3}{2}=\dfrac{7}{2}\)

g: \(F=\dfrac{8x^2-2x^2-4x^3+5x^3-4x^4+3x}{-3x^{-1}}\)

\(=\dfrac{-4x^4+x^3+6x^2+3x}{-3x^{-1}}=\dfrac{4}{3}x^5-\dfrac{1}{3}x^4-2x^3-x^2\)

Khi x=-1 thì F=-4/3-1/3+2-1

=-5/3+1

=-2/3