Question

phân tích các đa thuc sau thanh nhân tử

3x²-13x+10

x²-x-15/4

Answer 1

\(3x^2-13x+10=3x^2-3x-10x+10=3x\left(x-1\right)-10\left(x-1\right)=\left(x-1\right)\left(3x-10\right)\)

\(x^2-x-\dfrac{15}{4}=\left(x^2-x+\dfrac{1}{4}\right)-4=\left(x-\dfrac{1}{2}\right)^2-2^2=\left(x-\dfrac{5}{2}\right)\left(x+\dfrac{3}{2}\right)\)

Answer 2

a, 3x² - 13x +10

= 3x² - 3x - 10x + 10

= 3x(x - 1) - 10(x - 1)

= (3x - 10)(x - 1)

b, x² - x - \(\dfrac{15}{4}\)

= (x² - 2.\(\dfrac{1}{2}\).x + \(\dfrac{1}{4}\)) - 4

= (x - \(\dfrac{1}{2}\))² - 2²

= ( x - \(\dfrac{1}{2}\) + 2)(x - \(\dfrac{1}{2}\) - 2)