Systems of Equations and Inequalities Review

Marcie gets 3 points correct for every correct answer and loses 2 points for every incorrect answer. If she answered 25 questions and scored 40 points, write a system of equations.

What is the solution to the system of equations?

• (2,7)

• (-2,7)

• (-7,2)

• (2,-7)

• x = -2

• x = 2

• x = 8

• x = -8

What is the true when a system of equations has infinitely many solutions?

• The lines intersect in one place.

• The lines are parallel and do not intersect.

• The lines coincide (are the same line).

• This is impossible.

The zoo has 11 tigers and zebras on display. The number of tigers is one less than twice the number of zebras. Write a system of equations if t = number of tigers and z = number of zebras.

The difference of three times x and two times y is 12. The sum of x and y is 14.

Write two equations and use the to find the value of y.

https://www.desmos.com/calculator

• y = 8

• y = 6

• y = -8

• y = -6

What is the first step to solve the following system of equations using substitution?

2x - 5y = 12

3x + y = -2

• Add the equations together.

• Solve the second equation for y.

• Multiply the first equation by 3.

• Divide the second equation by 3.

What should be done to these equations in order to solve a system of equations by elimination?

-2x + 5y = 7

3x - 2y = -12

• Nothing needs to be done, since they both have -2's as coefficients.

• Multiply the first equation by 3.

• Multiply the first equation by 2 and the second equation by 3.

• Multiply the first equation by 3 and the second equation by 2.

• x = -8

• x = 8

• x = -3

• x = 3

• Graphing

• Substitution

• Elimination by addition

• Elimination by subtraction