Question

cho P(X)=2x^2+5x-1    Q(x)=2x^2-5x-7

a) tính P+Q

b) tính P-Q

Answer 1

\(a,P\left(x\right)+Q\left(x\right)=2x^2+5x-1+2x^2-5x-7=4x^2-8\)

\(b,P\left(x\right)-Q\left(x\right)=\left(2x^2+5x-1\right)-\left(2x^2-5x-7\right)=2x^2+5x-1-2x^2+5x+7=10x+6\)

Answer 2

a) P(x) + Q(x)

= (2x² + 5x - 1) + (2x² - 5x - 7)

= 2x² + 5x - 1 + 2x² - 5x - 7

= (2x² + 2x²) + (5x - 5x) + (-1 - 7)

= 4x² - 8

b) P(x) - Q(x)

= (2x² + 5x - 1) - (2x² - 5x - 7)

= 2x² + 5x - 1 - 2x² + 5x + 7

= (2x² - 2x²) + (5x + 5x) + (-1 + 7)

= 10x + 6