Systems by Substitution Steps

• Infinite number of solutions

• (0, 7)

• (-5, -7)

• (5, 7)

What is the first step in solving a system by Substitution?

• Make sure both equations are in standard form.

• Make sure at least one equation is solved for one variable.

• Make sure both equations are in slope-intercept form.

Why does substitution help us solve a system of equations?

• It changes one variable to an expression using the other variable, so we can solve an equation that only has one variable at a time.

• It creates a problem with fewer steps.

• It puts both equations in slope-intercept form for easy graphing.

TRUE or FALSE:

When both equations have the same variable isolated

(both y = or both x = ),

substituting the first into the second ends up looking like

you just set the two equal to each other.

• TRUE

• FALSE

What is the solution to this system? Solve by substitution.
y= 4x + 3
2x - 3y = 21

• (3,-9)

• (-3,-9)

• (-3,9)

• (0,1)

• (1, -4)

• (1, 4)

• (-4, -7)

• (-7, -4)

Solve this system by substitution.

• (1,-4)

• (1,4)

• (-4,-7)

• (-7,-4)

Which option shows the CORRECT substitution for this system?

Which option shows the CORRECT substitution for this system?

Which option shows the CORRECT substitution for this system?