Answer:
Step-by-step explanation:
(x-5)(x^2-2x-6)
x(x^2-2x-6)-5(x^2-2x-6)
x^3-2x^2-6x-5x^2+10x+30
Collect like terms
x^3-7x^2+4x+30
The second option is correct
2. (4a+5)^2=16a^2+Ba+25
Simplifying
(4a+5)^2=16a^2+Ba+25
(4a+5)(4a+5)=16a^2+Ba+25
4a(4a+5)+5(4a+5)=16a^2+Ba+25
16a^2+20a+20a+25=16a^2+Ba+25
16a^2+40a+25=16a^2+Ba+25
Comparing coefficient if a
Then 40a=Ba
Then B=40.
3. -5x^4(-3x^2+4x-2)
Simplifying and putting in mind that
-×-=+
-×+=-
Then, a^m×a^n=a^(a+b). Indices
15x^(4+2)-20x^(4+1)+10x^4
15x^6-20x^5+10x^4
The first option is the correct option.
4. 6xy^3z.3x^2yx^2
Using indices
a^m×a^n=a^(a+b)
(6×3)x^(1+2+2)y^(3+1)z
(18)x^(5)y^(4)z
18x^5y^4z
The second option is the correct option
