(-2a"b"' )( -3a)"

= ( -2a"b"' )( 9a ")

= - 18(a^4)(b"')

2

3x( 9x inches-3ax+a inches)

= 27x inches-9ax inches+3a inches x

three

(3x + 2y )( x - y)

= ( 3x + 2y )x - ( 3x + 2y )y

= 3x" + 2xy - 3xy - 2y "

= 3x" - xy - 2y "

four

(3x - 2y )( -2y - 3x)

= ( 2y - 3x )( 2y + 3x)

= 4y" - 9x "

five

(-4a - 1)"

= ( 4a + 1)"

= 16a" + 8a + 1

six

(3a + 2b - c )( 2b - 3a + c)

= [ 2b + ( 3a - c ) ][ 2b - ( 3a - c ) ]

= 4b" - ( 9a" - 6ac + c ")

= 4b" - 9a" + 6ac - c "

seven

(x - 3y )( x + y ) - ( x - 2y )( x + 2y ) - ( x - y)"

=(x-y-2y)(x-y+2y)-(x "-4y ")-(x-y)"

= ( x - y )" - 4y" - x" + 4y" - ( x - y)"

= - x "

eight

62 1" - 769 X 473 - 148 "

=(62 1+ 148)(62 1- 148)-769 X 473

= 769 X 473 - 769 X 473

= 0

nine

200 1" - 4002 + 1

= 200 1 "-2X 200 1x 1+ 1 "

= ( 200 1 - 1 )"

= 2000"

= 4000000

10

999" - 1002 X 998

= 999" - ( 1000 + 2 )( 1000 - 2 )

= 999" - 1000" + 2"

= ( 999 - 1000 )( 999 + 1000 ) + 4

= - 1999 + 4

= - 1995