nick used 1 3/4 kg of salt to melt the ice on his sidewalk. He then used another 3 4/5 kg on the driveway. How much salt did he use in all?

5 11/20

Step-by-step explanation:

1 3/4 + 3 4/5

Get a common denominator of 20

1 3/4 * 5/5   + 3  4/5 *4/4

1 15/20    + 3  16/20

4 31/20

Rewriting

4 + 20/20 + 11/ 20

4+1 + 11/20

5 11/20

see explanation

step-by-step explanation:

a

(6r + 7) + (13 + 7r) ( remove brackets and collect like terms )

= 6r + 7 + 13 + 7r

= 13r + 20

b

remove brackets and collect like terms

13 - r - 1 + r

= 12 - r

c

remove brackets and collect like terms

= - 8 - r + 2r - 4

= - 12 + r

d

remove brackets and collect like terms

= 7r - - - 6r

[-   - = - - = - ]

= r -