Question

Viết các biểu thức sau về dạng tích:

a. \(x^2-9\)

b. \(4x^2-1\)

c. \(9x^2-y^2\)

d. \(25x^2-9y^2\)

e. \(36x^2-25y^2\)

Answer 1

a) \(x^2-9\)

= \(x^2-3^2\)

\(=\left(x-3\right)\left(x+3\right)\)

b) \(4x^2-1\)

\(=\left(2x\right)^2-1^2\)

\(=\left(2x-1\right)\left(2x+1\right)\)

c) \(9x^2-y^2\)

\(=\left(3x\right)^2-y^2\)

\(=\left(3x-y\right)\left(3x+y\right)\)

d) \(25x^2-9y^2\)

\(=\left(5x\right)^2-\left(3y\right)^2\)

\(=\left(5x-3y\right)\left(5x+3y\right)\)

e) \(36x^2-25y^2\)

\(=\left(6x\right)^2-\left(5y\right)^2\)

\(=\left(6x-5y\right)\left(6x+5y\right)\)

Answer 2

a) \(x^2-9=x^2-3^2=\left(x-3\right)\left(x+3\right)\)

b) \(4x^2-1=\left(2x\right)^2-1^2=\left(2x-1\right)\left(2x+1\right)\)

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