How do you solve a system of equations by elimination? How do you solve a system of equations by substitution?

IF you have two equations with the 2 variables, x and y, you can substitute one y-value with the other, then solve.

Step-by-step explanation:  For example:

y = 2x + 4

3x+y = 9

We can substitute the value of y from the first equation, 2x + 4, into the second equation.  So, the second equaton becomes:

3x + 2x + 4 = 9

Now solve for x:

5x + 4 = 9

5x = 5

x = 1

This value of x then can be used to find y, by substituting in the value "1" for x in the first equation:

y = 2x + 4 = 2(1) + 4 = 2 + 4 = 6

So, the solution to this linear system is (1, 6)

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step-by-step explanation:

b is the right answer