Question

Which point is a solution of y = 3x and x + 2y = –21?
Select one:
a. (–3, –9)
b. (–9, –3)
c. (3, –9)
d. (–3, 9)

Answer 1

@AnswerMyQuestions

Answer 2

Use the x-values in the choices and plug them into the first equation, y = 3x/

Answer 3

Just plug in 3x for 'y' in the 2nd equation:

x + 2y = -21

x + 2(3x) = -21

Can you simplify that? @boricua5

Answer 4

So first, let's multiply -3 to it. -3 x 3 = ?

Answer 5

@boricua5

Answer 6

x + 2(3x) = -21

x + 6x = -21

7x = -21

Now we divide 7 to both sides, what's -21 / 7? @boricua5

Answer 7

@AnswerMyQuestions : \[-3 \times 3=9\]

Answer 8

@iGreen : -21 / 7 = -3

Answer 9

Yes, so the x-value is -3, so the answer is either A or D.

Now we can plug in x = -3 into any of the two equations.

y = 3x

y = 3(-3)

What's 3 * -3?

Answer 10

@boricua5

Answer 11

-9

Answer 12

Yep, so your answer is (-3, -9).

Answer 13

thanks .