Question

[Phạm Thu Hương]

cho f(x)=5x^3-7x^2+x+7

g(x)=7x^3 +2x+5

h(x)=2x^3 +4x+1

tính k(x)=f(x) -g(x) +h(x)

Answer 1

[👁💧👄💧👁]

Có: \(f\left(x\right)=5x^3-7x^2+x+7\)

\(g\left(x\right)=7x^3+2x+5\)

\(h\left(x\right)=2x^3+4x+1\)

\(\Rightarrow k\left(x\right)=f\left(x\right)-g\left(x\right)+h\left(x\right)\\ =5x^3-7x^2+x+7-7x^3-2x-5+2x^3+4x+1\\ =\left(5x^3-7x^3+2x^3\right)+\left(7-5+1\right)+\left(4x-2x+x\right)-7x^2\\ =0+3+3x-7x^2\\ =-7x^2+3x+3\)