Use elimination to find the x-coordinate for the solution to the following system:
4x – 3y = 20
2x + 6y = -5

Please select A, B, C or D.

A. 3.5

B. 35 6

C. 8.75

D. three-halves 3 2

A
Correct! You correctly multiplied and added to eliminate y and solve for x.

B
Incorrect. Check your addition, the coefficient of x is 10, not 6.

C
Incorrect. The equations were added incorrectly.

D
Incorrect. Multiply every term of the equation by the constant selected in order to obtain an equivalent equation.

Which of the following systems does not have (-2, 5) as a solution?

Please select A, B, C, or D.

A.

B.

C.

D.

A
Incorrect. The point (-2, 5) is the solution for this system.

B
Incorrect. The point (-2, 5) is the solution for this system.

C
Incorrect. The point (-2, 5) is one of the solutions for this system.

D
Correct! The point (-2, 5) only works in one of these equations so it cannot be a solution to the system.

During the no-calculator portion of a math contest, LaKeisha's team was asked to solve the following system.

If LaKeisha's team uses elimination, which equation could be used to accurately solve the system?

1. 2x² − 5x − 7 = 0
2. 2x² − 5x + 7 = 0
3. 2x² − 11x − 7 = 0
4. 2x² − 5x − 5 = 0

A
Correct! After multiplying the first equation by 2 and eliminating the y-terms, the resulting equation is set equal to zero.

B
Incorrect. An error was made setting the equation equal to zero.

C
Incorrect. An error was made when adding the two equations.

D
Incorrect. Multiply every term of the equation by 2 in order to obtain an equivalent equation.

Mr. Nguyen put the following system on the Algebra 2 test.

What is the correct solution?

A. (1, 2) and (-8, 9)
Incorrect. Only one point is a solution to the system of equations.

B. (-1, 2)
Incorrect. There are two points of intersection.

C. (1, 2) and (8, 9)
Incorrect. The equations were added incorrectly.

D. (-1, 2) and (-8, 9)
Correct! The line intersects the parabola at these two points.