Solving System by Substitution and Graphing

What is the best method do you use?

x = 6y − 11

−2x − 3y = −7

• Graphing, because they are both in slope-intercept form

• Substitution because a variable is isolated (solved for)

What is the best method to use?

y = −3x + 5

y = x -1

• Graphing, because they are both in slope-intercept form

• Substitution because a variable is isolated (solved for)

Solve this system by substitution.

• (1, -4)

• (1, 4)

• (-4, -7)

• (-7, -4)

The solution (x, y) to a system of equations is the set of numbers that make ...?

• All equations false

• At least one equation true

• All equations true

• At least one equation false

These two lines intersect at _____

• (4, -2)

• (4, 2)

• (-2, 4) 

• No solution

The ordered pair that satisfies BOTH equations in the system is called the _____________________

• system of equations

• function

• graph

• solution 

How many Solutions?

• One Solution

• No solution

• Infinitely Many Solutions

• (0, -1)

If the solution is infinitely many the lines will ________?

• intersect at exactly one point

• be parallel

• overlap each other

• never exist

In 3x + 2y = 10    and    x - 5y = 18, which variable should you isolate first?

• The x in the first equation

• The y in the first equation

• The x in the first equation

• The x in the second equation

Solve the system of equations using substitution:
y = 2x + 5
2x + 2y = 4

• (1, 7)

• (7, 1)

• (2, 9)

• (-1, 3)