Finding the value of x,y,z

This is part of a homework assignment that I cant seem to solve.

Create, save and run a script that solves the following set of equations for user-supplied values of a, b, and c. Check your script with the values of a=95, b=-50, and c=145. Set of equations are:

7x+14y-6z=a

12x+5y+9z=b

-5x+7y+15z=c

My code right now is

an1 = 'Give me a'
a = input(an1);
an2 = 'Give me b'
b = input(an2);
an3 = 'Give me c'
c = input(an3);
syms x y z
eq1 = (7*x)+(14*y)-(6*z)== a;
eq2 = (12*x)+(5*y)+(9*z)== b;
eq3 = (-5*x)+(7*y)+(15*z)== c;
x,y,z = solve(eq1,eq2,eq3, x,y,z)
x,y,z = solve(eq1,eq2,eq3, x,y,z)
z,y,z = solve(eq1,eq2,eq3, x,y,z)

Does anyone know how I could find the values of x, y, and z from these functions?

Final Code, thanks for the help Image Analyst

an1 = 'Give me a'
a = input(an1);
an2 = 'Give me b'
b = input(an2);
an3 = 'Give me c'
c = input(an3);
X = [7, 14, -6;
     12, 5, 9;
     -5, 7, 15]
Y = [a; b; c] 
coefficients = X \ Y

Answer 1

[Image Analyst]

Try a matrix division:

% 7x+14y-6z=a
% 12x+5y+9z=b
% -5x+7y+15z=c
X = [7, 14, -6;
	12, 5, 9;
	-5, 7, 15]
Y = [11; 22; 33] % Whatever it may be.
% Solve for the coefficients, using a least squares approach.
coefficients = X \ Y
% Double check to see if we get back a, b, and c
a2 = 7 * coefficients(1) + 14 * coefficients(2) - 6 * coefficients(3)
b2 = 12 * coefficients(1) + 5 * coefficients(2) + 9 * coefficients(3)
c2 = -5 * coefficients(1) + 7 * coefficients(2) + 15 * coefficients(3)

[Benjamin Beaugrand]

That unfortunately didn't work.

[Image Analyst]

I actually ran it, and it did work.

X =

7 14 -6

12 5 9

-5 7 15

Y =

11

22

33

coefficients =

0.070967741935484

1.41935483870968

1.56129032258065

a2 =

11

b2 =

22

c2 =

33

Did you put back in the questions asking for a, b, and c, and uncomment the line?

Y = [a; b; c] % Whatever the user enters.
% Y = [11; 22; 33] % For example, use these values...

What values did you put for a, b, and c that caused it not to work?

[Benjamin Beaugrand]

This is the code after plugging it in, I'm guessing I mdid it wrong.

an1 = 'Give me a'
a = input(an1);
an2 = 'Give me b'
b = input(an2);
an3 = 'Give me c'
c = input(an3);
syms x y z
%(7*x)+(14*y)-(6*z)== a;
%(12*x)+(5*y)+(9*z)== b;
% (-5*x)+(7*y)+(15*z)== c;
X = [7, 14, -6;
     12, 5, 9;
     -5, 7, 15]
% Y = [a; b; c] % Whatever the user enters.
Y = [a; b; c] % For example, use these values...
% Solve for the coefficients, using a least squares approach.
coefficients = x \ y

[Benjamin Beaugrand]

I corrected the missuse of your code and got the answer

X =

7 14 -6

12 5 9

-5 7 15

Y =

95

-50

145

coefficients =

-9.7742

12.0161

0.8011

Thank you for the help.

[Image Analyst]

MATLAB is case sensitive so

coefficients = X \ Y

is not the same as

coefficients = x \ y

Answer 2

[Sandeep Raut]

Find the values of x and y using MATLAB commands, also solve the equation and justify how your commands work

4y+3x=100

4y−19x=12

[Image Analyst]

How is this an answer to Benjamin's question?