Question

What is the value of x in the proportion x+1/x+3=15/21
i need help can some one help me with the steps

Answer 1

you could try cross multiplying

\[\frac{ a }{ b } = \frac{ c }{ d } \rightarrow ad = bc\]

in this case:

\[\frac{ x + 1 }{ x + 3 } = \frac{ 15 }{ 21 } \rightarrow (x+1) * 21 = (x + 3) * 15\]

Answer 2

so it would be 3x=1x ?

Answer 3

well we have

(x + 1) * 21 = (x + 3) * 15

this is the same as

21x + 21 = 15x + 45

Answer 4

i have no idea what im doing sorry

Answer 5

you have to solve this algebra problem for x:

21x + 21 = 15x + 45

Answer 6

can you do a example problem ?