Question

Tính:
1) \(\left(5x^2-2\right)\)\(\left(5x^2+2\right)\)
2) \(\left(2a+\frac{1}{2}\right)+\left(2a-\frac{1}{2}\right)\)
3) \(\left(3x^2-y\right)\left(3x^2+y\right)\)
4) \(\left(\frac{1}{2}x-1\right)\left(\frac{1}{2}x+1\right)\)
5) \(\left(\frac{3}{4}x+2\right)\left(\frac{3}{4}x-2\right)\)
6) \(\left(\frac{1}{2}x^2-5y\right)^2\)
7) \(\left(1+3a^2\right)\left(3a^2-1\right)\)

Answer 1

áp dụng các hằng đẳng thức đáng nhớta được :

1)25x^4-4

2)4a^2-1/4

3)9x^4-y^2

4)1/4x^2-1

5)9/16x^2-4

6)1/4x^4-(5x^2)y+25y^2

7)9a^4-1