Question: BT2/ THỰC HIỆN PHÉP NHÂN:
1) $(x-1)(x-2)$
2) $(x+3)(x-4)$
3) $(x+5)(1-x)$
4) $(2x-1)(3x+2)$
5) $(4x+3)(2-x^2)$
6) $(-x^2+1)(3x^2-x)$
7) $(3x-2x^2)(2x-1)$
8) $(4x^2-3x)(5x+2)$
9) $(5x^2+4)(3-2x^2)$
10) $(2x+3)(x^2-x+1)$
11) $(x-3)(x^2+2x-4)$
12) $(3x^2-2x)(-3x^2+5x-3)$
13) $(2x^2-2x-1)(4x^2-5x+2)$
14) $(x^2-4x+5)(-2+x^2+3x)$
1. **Problem:** Multiply $(x-1)(x-2)$.
2. **Formula:** Use distributive property: $(a+b)(c+d) = ac + ad + bc + bd$.
3. **Calculation:**
$$
(x-1)(x-2) = x\cdot x + x\cdot(-2) + (-1)\cdot x + (-1)\cdot(-2) = x^2 - 2x - x + 2
$$
4. **Simplify:**
$$
x^2 - 2x - x + 2 = x^2 - 3x + 2
$$
**Final answer:** $x^2 - 3x + 2$.
Steps for the first problem only as per instructions.