[6.03] Part 1: Decide whether you would use the graphing, substitution, or elimination method to solve the following system of equations. Explain, in complete sentences, why you chose that method. Part 2: Solve the following system of equations and show all of your work. 2x + 5y = −3 −15x − 5y = −10

Question

[6.03] Part 1: Decide whether you would use the graphing, substitution, or elimination method to solve the following system of equations. Explain, in complete sentences, why you chose that method. Part 2: Solve the following system of equations and show all of your work.     2x + 5y = −3 −15x − 5y = −10

anonymous · Answer

I would use the elimination method because when the two equations are added, the y's automatically cancel each other out.

2x + 5y = -3
-15x - 5y = -10
---------------add
-13x = -13
x = 1

now sub 1 in for x in either of the original equations to find y
2x + 5y = -3
2(1) + 5y = -3
2 + 5y = -3
5y = -3-2
5y = -5
y = -1

check...
-15x - 5y = -10
-15(1) - 5(-1) = -10
-15 + 5 = -10
-10 = -10 (correct)

any questions ?