Question

5. f(x) = 3x³ - 4x² +6x and g(x)=5x ³+ 2x²- 3x. What is f(x) - g(x)?

A. -2x³ - 6x² +9x
B. -2x³ - 6x² – 3x
C. 2x³+ 6x² + 3x
D. 8x³ - 6x² -9x​

Answer 1

A. -2x³ - 6x² + 9x

Explanation:

`f(x)=3x^3-4x^2+6x\\\\g(x)=5x^3+2x^2-3x\\\\f(x)-g(x)=(3x^3-4x^2+6x)-(5x^3+2x^2-3x)\\\\=3x^3-4x^2+6x-5x^3-2x^2-(-3x)\qquad\text{combine like terms}\\\\=(3x^3-5x^3)+(-4x^2-2x^2)+(6x+3x)\\\\=-2x^3-6x^2+9x`