Question

Solve the following system of equations by the substitution method.

5x = y + 6
2x - 3y = 4

What is the value of the y-coordinate?

Answer 1

Any ideas?

Answer 2

What does the word "substitution" mean to you?

Answer 3

from the first equation y=5x-6
insert this into the second equation

Answer 4

to subtract from another number

Answer 5

No, that would be "subtraction" this word is "substitution."

Answer 6

Substitution is the process of substituting one thing for another.

Answer 7

Like a substitute teacher is a teacher who is used as replacement for your regular teacher, right?

Answer 8

ah alright

Answer 9

The substitution principle states an expression may be replaced by another expression that has the same value.

Like 4 + 2 can be replaced by 6 because 4 +2 and 6 have the same value, right?
Here 4 + 2 and 6 are called numerical expressions.

Answer 10

Ok

Answer 11

This principle can be generalized to variable expressions as well, like 4x + 2x can be replaced by 6x because 4x + 2x = (4 + 2)x = 6x, using the distributive property.

Answer 12

Ok im stating to understand

Answer 13

Good :-)

Answer 14

would that mean the answer would be like 14/13?

Answer 15

That is the answer for the x value. The question asks for the y value.

Solve the following system of equations by the substitution method.

5x = y + 6
2x - 3y = 4

What is the value of the y-coordinate?

Answer 16

So use the principle of substitution and replace an x with 14/13 and solve for y.

Answer 17

would the answer be -16?

Answer 18

You can check to see if your answer is correct by substitution into the the original equation to see if you get a true statement.

Answer 19

I get y = -8/13.