Question if-the
1.4 Systems of Two Linear Equations - Substitution method
0:00
If the system of equations above has solution 
, what is the value of 
?
A.
0
B.
9
C.
18
D.
38
If the system of equations above has solution , what is the value of ?
Hard-difficulty · SAT Math · Systems of Two Linear Equations — Substitution method. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.
Answer explanation
Choice C is correct. Adding the given equations yields 9x + 9y = 162. Dividing each side of the equation 9x + 9y = 162 by 9 gives x + y = 18.
Choice A is incorrect and may result from incorrectly adding the equations. Choice B is incorrect and may result from conceptual or computational errors. Choice D is incorrect. This value is equivalent to y – x.
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