You are here:

Question
Find the values of x, y, z if :-
5x + 20y + 50z = 500
&
x + y + z = 20

Questioner:Prateek
Country:India
Private:No
Subject:Maths
Question:

Find the values of x, y, z if :-
5x + 20y + 50z = 500
&
x + y + z = 20
...................................
Sincy you have two equations and three variables, you will need a parameter.

Start by reducing:

5x + 20y + 50z = 500
to

x + 4y + 10z = 100  (you could have done that)
Take x + y + z = 20  and solve:

x = 20 - y - z

Substitute:

(20 - y - z) + 4y + 10z = 100

3y + 9z = 80

Now set z = t  (it could be y, and you could choose any parameter) and

1. Solve for y in terms of t.
2. Go back and solve for x in terms of t.

Done.

Volunteer

#### Paul Klarreich

##### Expertise

I can answer questions in basic to advanced algebra (theory of equations, complex numbers), precalculus (functions, graphs, exponential, logarithmic, and trigonometric functions and identities), basic probability, and finite mathematics, including mathematical induction. I can also try (but not guarantee) to answer questions on Abstract Algebra -- groups, rings, etc. and Analysis -- sequences, limits, continuity. I won't understand specialized engineering or business jargon.

##### Experience

I taught at a two-year college for 25 years, including all subjects from algebra to third-semester calculus.

Education/Credentials
-----------