Given the quadratic 7x2 +6x– 1,

Step-by-step explanation:

7x^2+7x-x-1

7x(X+1) -1(X+1)

(7x-1) (x-1)

X=1/7 , 1

( i ) - 160

( ii ) 304

( iii ) 24975

( iv ) 4455

( v ) 270000

( vi ) 28000

( vii ) - 5625

( viii ) - 4590

Step-by-step explanation:

( i )

25 x ( - 40 ) + ( - 40 ) x 15

= - 40 x ( 25 + 15 )

= - 40 x 40

= - 160

( ii )

8 x ( 40 - 2 )

= 8 x 38

= 304

( iii )

25 x 999

= 25 x ( 1000 - 1 )

= 25 ( 1000 ) - 25 ( 1 )

= 25000 - 25

= 24975

( iv )

45 x 91

= 45 x ( 100 - 1 )

= 45 ( 100 ) - 45 ( 1 )

= 4500 - 45

= 4455

( v )

8 x 54 x 625

= 54 x ( 8 x 625 )

= 54 x 5000

= 270000

( vi )

- 7 x ( - 20 ) x 40 x 5

= [ - 7 x ( - 20 ) ] x [ 40 x 5 ]

= 140 x 200

= 28000

( vii )

625 x ( - 8 ) + ( - 625 )

= 625 x ( - 8 - 1 )

= 625 x ( - 9 )

= - 5625

( viii )

( - 45 ) x 102

= - 45 x ( 100 + 2 )

= - 45 ( 100 ) - 45 ( 2 )

= - 4500 - 90

= - 4590