The Substitution Method

I don't know what a chef has to do with the substitution method, but oh well... dAnd now, the moment you've all been waiting for:

IT'S TIME TO LEARN ABOUT THE SUBSTITUTION METHOD!!!!!

The Steps:

Step 1: fSolve one of the equations for one of its variables.
Step 2: gSubstitute the expression from Step 1 into the other equation and solve for the other variable.
Step 3: fSubstitute the value from Step 2 into the revised equation from Step 1 and solve.

 

Now, using those steps, let's try to solve a linear system using substitution!

3x + 4y = -4 fffffffffEquation 1

dddddddddddddddddddddddddddddddddddddddddddddddd x + 2y = 2 ssssssssEquation 2

dddddddddddddddddddddddddddddddd

SOLUTION:

1. sSolve equation 2 for x.

sdfddddddssss s x + 2y = 2dddddddddWrite Equation 2.

ssffffffffff dddfffx = -2y + 2ffffffffff fff Revised Equation 2

2. hSubstitute the expression for x into Equation 1 and solve for y.

ffffffffffff fffffff3x + 4y = -4ssssssssssWrite Equation 1.

ff ssss 3(-2y + 2) + 4y = -4 sa fffffffff Substitute -2y + 2 for x.

hhhhhhhhhhhhhhhhh y = 5ddddddddd Solve for y.

3. fSubstitute the value of y into revised Equation 2 and solve for x.

fffffffffffdddddd x = -2y + 2ggggggggg Write revised Equation 2.

fffffffffffffffffffx = -2(5) + 2ddddddddd Substitute 5 for y.g

ggsssssssssssdgggg xf=f-2f ff ssssssssSimplify.f

  • The solution is (-8, 5).ff

Now that wasn't so bad, was it??

 

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