Posted by mike on Friday, December 18, 2009 at 7:17pm.
I did a problem and used the substitution method and it took me forever to solve by hand. Is there a shorter way to show how this problem was done. The problem was
x+y+z=7,xy+2z=7,2x+y+3z=15
The final answer came out to be
x=4
z=2
y=1

Algebra Question  Reiny, Friday, December 18, 2009 at 11:36pm
This problem just "begs" to be done by elimination, look at the y values
add #1 and #2 2x + 3z = 14 #4
add #2 and #3 3x + 5z = 22 #5
triple #4  6x + 9z = 42
double #5  6x + 10z = 44
subtract #5  #4
z = 2
sub into #4  2x+6 = 14 , x = 4
back into #1
4 + y + 2 = 7
y = 1
Answer This Question
Related Questions
 algebra  Here is my question. How do you solve th substitution method in this ...
 Substitution MethodPlz help  Use the Substitution method to solve the system ...
 Algebra 1  bobpursey, In this problem you helped me with earlier: Solve using ...
 Calculus  Given two problems: Problem A: Tau = Integral(0 to v) v/(q^2  v^2) ...
 Grade 11th Maths  (Second Time posting this problem)This problem is related to ...
 Algebra  The problem is 9x+4y=12 x=265y Solve by substitution method
 Honors Algebra II  I've been stuck on a problem with my homework for a couple ...
 Algebra  Use the above graph of f(x) to complete the following table for ...
 Math  How would you solve this problem?: x2 + y2 = 25 x2  y = 5 You have to ...
 Geometry  Complete Problem #28 in Section 1.5 Exercises (Chapter 1) of ...
More Related Questions