How Can You Solve This Modulus Equation with Square Roots and Absolute Values?

  • Thread starter Thread starter chwala
  • Start date Start date
  • Tags Tags
    Modulus
Click For Summary
SUMMARY

The discussion focuses on solving the modulus equation 2|3x+4y-2| + 3√(25-5x+2y) = 0. The user successfully derives two simultaneous equations: 3x + 4y = 5 and -5x + 2y = -21, leading to approximate solutions of x ≈ 3.615 and y ≈ -1.46. The approach involves equating the non-negative terms independently, confirming that both must equal zero for the equation to hold true.

PREREQUISITES
  • Understanding of modulus equations and their properties
  • Familiarity with square roots and their implications in equations
  • Basic algebraic manipulation skills
  • Knowledge of solving simultaneous equations
NEXT STEPS
  • Study methods for solving modulus equations in depth
  • Learn techniques for handling square roots in algebraic equations
  • Explore graphical methods for visualizing the intersection of linear equations
  • Investigate advanced algebraic techniques for simplifying complex equations
USEFUL FOR

Students and educators in mathematics, particularly those focusing on algebra, as well as anyone looking to enhance their problem-solving skills in equations involving absolute values and square roots.

chwala
Gold Member
Messages
2,828
Reaction score
421
Homework Statement
##2|3x+4y-2|##+##3####\sqrt{25-5x+2y}##=##0##
Relevant Equations
Modulus
I am trying to go through my old notes ...i came across this question,i do not have the solution.

Solve ##2|3x+4y-2|##+##3####\sqrt{25-5x+2y}##=##0##
Ok my approach on this;
##3####\sqrt{25-5x+2y}##=##-2|3x+4y-2|##
##9(25-5x+2y)=4(3x+4y-2)^2##
##9(25-5x+2y)=4(9x^2+16y^2+24xy-12x-16y+4)##
##9(25-5x+2y)=4[(3x+4y)(3x+4y)-4(3x+4)+4]##
Let ##p=(3x+4y)## and ##m=(2y-5x)##
Then it follows that
##9(25+m)=4(p^2-4p+4)##
##\frac {9}{4}##=##\frac{p^2-4p+4}{25+m}##
ok at this part i equated the numerators i.e
##(p-2)^2=9##
##→p-2=±3##, ##p=5## or ##p=-1##
and on equating the denominator, i have ##4=25+m##→##m=-21##

From this using ##p=5##, and substituting in the problem, i end up with the simultaneous equation;
##3x+4y=5##
##-5x+2y=-21##,
##x≈3.615## and ##y≈-1.46##, i substituted these values into the original equation and they both satisfy the equation...
Any comments or better way of approaching the problem? Cheers guys
 
Last edited:
Physics news on Phys.org
chwala said:
Solve ##2|3x+4y-2|##+##3####\sqrt{25-5x+2y}##=##0##
Both terms are non-negative so have to be zero independently, yes? The solution is the intersection of two straight lines.
 
  • Love
Likes   Reactions: Delta2

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
Replies
4
Views
2K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
8
Views
3K
Replies
10
Views
3K
Replies
4
Views
2K
Replies
19
Views
2K
Replies
8
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K