Question 5-y-10

1.4 Systems of Two Linear Equations - Elimination method
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5 y = 10 x + 11

- 5 y = 5 x - 21

The solution to the given system of equations is x,y. What is the value of 30 x ?

Enter your answer:

5 y = 10 x + 11 - 5 y = 5 x - 21 The

Hard-difficulty · SAT Math · Systems of Two Linear Equations — Elimination method. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

The correct answer is 20 . Adding the first equation to the second equation in the given system yields 5y-5y=10x+5x+11-21, or 0=15x-10. Adding 10 to both sides of this equation yields 10=15x. Multiplying both sides of this equation by 2 yields 20=30x. Therefore, the value of 30 x is 20 .