Solve for x.
12: 15 = x: 5
04
36
60

12:15 = x:5

Cross multiply:

(12 * 5) = (15 * x)

Simplify:

60 = 15x

Divide both sides by 15:

x = 60/15

x = 4

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 -