8 questions on multiplication of integers in the second grade of junior high school, reward 100 + additional reward 100, ***200, a brief process is required

a?-(a＋3)(a-5)＝a?-(a?-2a-15)=a?-a?+2a+15=2a+15

(2)－3x?(－x?y＋2y－1)

=3x^4y-6x?y+3x?

(3)a?(a－1) +2a(a?-2a+3)

=a?-a?+2a?-4a?+6a

=3a?-5a?+6a

(4)(3x)?－(3x＋2y)(3x－2y)

=9x?-(9x?-4y?)

=9x?-9x?+4y?

=4y?

(5)x?(x?－x＋1)－x(x?－x?－1)

=x^4 -x?+x?-x^4+x?+x

=x?+x

S=na+(b-n)n=na+bn-n?=( a+b)n-n?=(a+b-n)n

Simplified evaluation: 3x(2x?-x+1)-2(2x-3)-4(1-x?), where x =-2

3x(2x?-x＋1)-2(2x-3)-4(1-x?)

=6x?-3x?+3x-4x+ 6-4+4x?

=6x?+x?-x+2

x=-2

Original formula=6*(-2) ?+(-2)?-(-2)+2

=-48+4+2+2

=-40

Solve the inequality: (2x－3)(x－4)－(x＋2)(x－3)≥x?－8

2x?-8x-3x+12-(x?-3x+2x-6) ≥x?-8

2x?-11x+12-(x?-x-6)≥x?-8

2x?-11x+12-x?+x +6≥x?－8

x?-10x+18-x?+8≥0

-10x≥-26

x≤2.6< /p>

Participating in the "Little Master Cup" photography competition in a certain city, Xiao Ming enlarged the photos of classmates participating in tree planting activities to a length of a cm and a width of 3a/4cm, and carefully added a width of 2 With a wooden frame of cm, find the area of ??Xiao Ming’s photographic work.

(3a/4+4)*2+(a+2)*2+(3a/4+2)*2+2a+a*3a/4

= 3a/2+8+2a+4+3a/2+a+2a+3a?/4

=3a?/4+7a+16