A rectangle mesures 3 cm by 6 cm Three of these rectangles are put together to make a larger rectangle. Work out the perimeter of this larger rectangle: It mesures three 3 cm tall rectangles that are both 6cm each and another one that is 6 cm tall.

45 cm

Step-by-step explanation:

Assuming the rectangles r put together as per the attached picture.

length = 6+3 = 9 cm

Width = 3+3 = 6cm

Perimeter = 2(l+w)

P = 3(9+6)

P = 3 * 15

P = 45 cm

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 -