Question

Rút gọn :

A=\(\left(x-6\right)^2+\left(x+6\right)^2\)

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

C=\(\left(5x-2\right)\cdot\left(5x+2\right)-\left(5x-1\right)^2\)

D=\(\left(100^2+98^2+96^2+...+2^2\right)-\left(99^2+97^2+95^2+...+1^2\right)\)

Answer 1

a)

\(A=\left(x-6\right)^2+\left(x+6\right)^2\)

\(A=\left(x^2-2x6+6^2\right)+\left(x^2+2x6+6^2\right)\)

\(A=x^2-2x6+6^2+x^2+2x6+6^2\)

\(A=\left(x^2+x^2\right)+\left(-2x6+2x6\right)+\left(6^2+6^2\right)\)

\(A=2x^2+72\)

b)

\(B=\left(x^2+y^2+3^2+2xy+2x3+2y3\right)-\left(x^2+y^2+9\right)\)

\(B=x^2+y^2+3^3+2xy+2x3+2y3-x^2-y^2-9\)

\(B=\left(x^2-x^2\right)+\left(y^2-y^2\right)+\left(3^2-9\right)+2xy+2x3+2y3\)

\(B=2xy+2x3+2y3\)

Mình phải đi ngủ rồi, có gì mai làm tiếp nha

Answer 2

c/

C = (5x - 2) . (5x + 2) - (5x - 1)²

C = [(5x)² - 2²] - [(5x)² - 2 . 5x1 + 1²]

C = (5x)² - 2² - (5x)² + 2 . 5x1 - 1²

C = [(5x)² - (5x)²] + (-2² + 2 - 1²) + 5x1

C = 5 + 5x1.