what is the value of x in the proportion x+1/x+3=15/21

1 answer

To solve for x in the proportion (x+1)/(x+3) = 15/21, we will cross-multiply.

Cross-multiplying, we get:

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

Expanding the equation:

21x + 21 = 15x + 45

Subtracting 15x from both sides:

6x + 21 = 45

Subtracting 21 from both sides:

6x = 24

Dividing both sides by 6:

x = 4

Therefore, the value of x in the proportion is 4.