P= a + b + c; P = 28, a =5, b = 11 (Perimeter of a triangle)

c = 12.

Step-by-step explanation:

Fill in what you know. 28 = 5 + 11 + c. Add 5 and 11 together. 28 = 16 + c. Then subtract 16 from both sides 28 - 16 = 16 - 16 +c. Then the number you have left is your answer.

c=12

Step-by-step explanation:

P=a+b+c

28=5+11+c ; combine 5 and 11.

28=16+c ; subtract 16 from each side to get c

28-16=12

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

-1   1/6.   you dont subtract the denominators

step-by-step explanation: