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)

salary

step-by-step explanation:

option c) graph of line going through 1, 4 and 3, 10

step-by-step explanation:

let y equal to margo's coin collection

let x equal to number of years

at the begining x=0, y=1 → point=(x,y)→point=(0,1)

she adds 3 coins per year, then y=1+3x

at x=1, y=1+3(1)=1+3→y=4→point=(x,y)→point=(1,4)

at x=3, y=1+3(3)=1+9→y=10→point=(x,y)→point=(3,10)

the graph of line going through (1, 4) and (3, 10), then the option c is the correct.