有幾條數學.要有步驟ar...我吾識做...help ME..急!!

1.(m-1)(m-6)
=m^2-6m-m+6
=m^2-7m+6

2.(2y-5)(y+7)
=2y^2+14y-5y-35
=2y^2+9y-35

3.(7z-1)(z-7)
=7z^2-49z-z+7
=7z^2-50z+7

4.(4+c)(5-c)
=20-4c+5c-c^2
=20+c-c^2


5.(5m+4n)(m-4n)
=5m^2-20mn+4mn-16n^2
=5m^2-16mn-16n^2

6.(3x-2y)(-3y-2x)
= -9xy-6x^2-6y^2+4xy
=-6x^2-6y^2-5xy

1.X

2.(2y-5)(y+7)
=2y-5xy+7
=2y+yx5+7
=3yx12

3.(7z-1)(z-7)
=7z-1xz-7
=7z-zx1-7
=6zx-1

4.(4+c)(5-c)
=4+cx5-c
=4+5xc-c
=9

5.(5m+4n)(m-4n)
=5m+4nxm-4n
=5m+mx4n-4n
=6m

6.X

1. (m-1)(m-6)
= m(m-6)-(m-6)
= m^2-6m-m+6
= m^2-7m+6

2. (2y-5)(y+7)
= 2y(y+7)-5(y+7)
= 2y^2+14y-5y-35
= 2y^2+9y-35

3.(7z-1)(z-7)
= 7z(z-7)-(z-7)
= 7z^2-49z-z+7
= 7z^2-50z+7

4.(4+c)(5-c)
= 4(5-c)+c(5-c)
= 20-4c+5c-c^2
= 20+c-c^2

5.(5m+4n)(m-4n)
= 5m(m-4n)+4n(m-4n)
= 5m^2-20mn+4mn-16n^2
= 5m^2-16mn-16^2

6.(3x-2y)(-3y-2x)
= 3x(-3y-2x)-2y(-3y-2x)
= -9xy-6x^2+6y^2+4xy
= -5xy-6x^2+6y^2