Homework post by @professorlenz || LESSON 3 - Solving linear equations by substitution method || 21-7-22

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Good evening to everyone in this community. I'm happy for the opportunity given to me to take up the homework about simultaneous equation taught by @whileponderin. The answers to the homework are:

Question 1

Solve the following linear equations using substitution method

x+y=7------(1)
x-y=8-------(2)

Making x subject of the formula
x=7-y-----(3)

Substituting for x in equation 2(x-y=8)

7-y-y=8
7-2y=8
Collect like terms
-2y=8-7
-2y=1
Divide both sides by -2
-2y/2=1/2
y= -0.5

Substitute -0.5 for y in equation 1(x+y=7)

x-0.5=7
x=7+0.5
x= 7.5

Question 2

Solve the same linear equation given in question 1 again but this time pick the second equation and make y the subject of formula while solving.

Solution

x+y=7
x-y=8

Making y subject of the formula
-y=7-x

Substitute 7-x for y in the equation

x-(7-x)=8
x-7+x=8
2x=8+7
2x= 15
Divide both sides by 2
2x/2=15/2
x= 7.5

Substitute 7.5 for x into equation 1(x+y=7)

7.5+y=7
y=7-7.5
y=-0.5

Question 3

Check if your values for "x" and "y" are correct by using the method taught by the class

Equation 1: x+y=7
If x=7.5 and y=-0.5,

7.5+(-0.5)= 7

The solution is correct

Equation 2: x-y=8
If x=7.5 and y=-0.5

7.5-(-0.5)=8

The solution is correct...

Thanks a lot @whileponderin

Cc,
@ngoenyi
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