Bài tập Những hằng đẳng thức đáng nhớ (có lời giải chi tiết)

A. ${\left(A + B\right)}^2 = A^2 + 2AB + B^2$

B. ${\left(A + B\right)}^2 = A^2 + AB + B^2$

C. ${\left(A + B\right)}^2 = A^2 + B^2$

D. ${\left(A + B\right)}^2 = A^2 - 2AB + B^2$

A.$(A – B)(A + B) = A^2 + 2AB + B^2$

B. $\left(A + B\right)\left(A – B\right) = A^2 – B^2$

C. $\left(A + B\right)\left(A – B\right) = A^2 – 2AB + B^2$

D. $\left(A + B\right)\left(A – B\right) = A^2 + B^2$

A. ${(x + y)}^2 = (x + y)(x + y)$

B. $x^2 – y^2 = (x + y)(x – y)$

C. ${(-x – y)}^2 = {(-x)}^2 – 2(-x)y + y^2$ 

D. $(x + y)(x + y) = y^2 – x^2$

A. ${\left(x + 2y\right)}^2 = x^2 + 4xy + 4y^2$

B. ${\left(x - 2y\right)}^2 = x^2 - 4xy + 4y^2$

C. ${\left(x - 2y\right)}^2 = x^2 - 4y^2$

D. $(x – 2y)(x + 2y) = x^2 – 4y^2$

A. (4x – 5y)(4x + 5y)

B. (4x – 25y)(4x + 25y)

C. (2x – 5y)(2x + 5y)

D. ${(2x – 5y)}^2$

A. $\left(\frac{x}{9}-\frac{y}{64}\right)\left(\frac{x}{9}+\frac{y}{64}\right)$

B. $\left(\frac{x}{3}-\frac{y}{4}\right)\left(\frac{x}{3}+\frac{y}{4}\right)$

C. $\left(\frac{x}{9}-\frac{y}{8}\right)\left(\frac{x}{9}+\frac{y}{8}\right)$

D. $\left(\frac{x}{3}-\frac{y}{8}\right)\left(\frac{x}{3}+\frac{y}{8}\right)$

A. $9x^2 – 24xy + 16y^2$

B. $9x^2 – 12xy + 16y^2$ 

C. $9x^2 – 24xy + 4y^2$ 

D. $9x^2 – 6xy + 16y^2$

A.  $\frac{x^2}{4}-xy+4y^2$

B. $\frac{x^2}{4}-2xy+4y^2$

C.  $\frac{x^2}{4}-2xy+2y^2$

D. $\frac{x^2}{2}-2xy+2y^2$

A. ${\left(\frac{1}{4xy+1}\right)}^2$

B. ${\left(\frac{1}{2}xy+1\right)}^2$

C. ${\left(xy-\frac{1}{2}\right)}^2$

D. ${\left(\frac{1}{2}xy-1\right)}^2$

A. ${\left(5x – 2y\right)}^2$ 

B. ${\left(2x – 5y\right)}^2$

C. ${\left(25x – 4y\right)}^2$

D. ${\left(5x + 2y\right)}^2$

A. ${(c + d)}^2 – {(a + b)}^2 = (c + d + a + b)(c + d – a + b)$

B. ${(c – d)}^2 – {(a + b)}^2 = (c – d + a + b)(c – d – a + b)$

C. $(a + b + c – d)(a + b – c + d) = {(a + b)}^2 – {(c – d)}^2$

D. ${(c – d)}^2 – {(a – b)}^2 = (c – d + a – b)(c – d – a – b)$

A. $4 –{\left(a + b\right)}^2 = (2 + a + b)(2 – a + b)$

B. $4 –{\left(a + b\right)}^2 = (4 + a + b)(4 – a - b)$

C. $4 –{\left(a + b\right)}^2 = (2 + a - b)(2 – a + b)$

D. $4 –{\left(a + b\right)}^2 = (2 + a + b)(2 – a - b)$

A. -15x + 1

B. 1

C. 15x + 1

D. – 1

A. 342

B. 243

C. 324

D. -324

A. 0

B. 1

C. 19

D. – 19 

A. B < 12

B. B > 13

C. 12 < B< 14

D. 11 < B < 13

A. D = 14C + 1

B. D = 14C

C. D = 14C – 1

D. D = 14C – 2 

A. 2N – M = 60

B. 2M – N = 60

C. M> 0, N < 0

D. M > 0, N > 0

A. 0

B. 1

C. 2

D. 3

A. 0

B. 1

C. 2

D. 3