Respuesta :

Answer:

Bill is 25 years old and Jenny is 29 years old

Step-by-step explanation:

Systems of Equations:

J = 4 + B

J + B = 54

Substitute J into the first equation.

4 + B + B = 54

Add like terms.

4 + 2B = 54

Isolate the variable.

4 + 2B = 54

-4            -4

2B = 50

2B/2 = 50/2

B = 25 years old

Plug in B into the second equation of the system.

J + B = 54

J + 25 = 54

Isolate the variable.

J + 25 = 54

   -25   -25  

J = 29 years old

Check your answer. Pick whatever equation in the system and plug in your answers.

J = 4 + B

29 = 4 + 25

29 = 29