(i haven't been taught this lesson yet but i would like to answer this question) Which values of x will make the absolute value equation true?

|x – 3| = 40
A.
{–43, –37}
B.
{43, –37}
C.
{40, –40}
D.
{43, 37}

Question

(i haven't been taught this lesson yet but i would like to answer this question) Which values of x will make the absolute value equation true?

|x – 3| = 40
A.
{–43, –37}
B.
{43, –37}
C.
{40, –40}
D.
{43, 37}

anonymous · Answer

To solve this, substitute values of x given in your multiple choice into the equation given.

anonymous · Answer

Example, |x-3| = 40. Let's try the x values given in A. x = , -43, and -37.
Let's do x=-43 first.
|(-43) - 3| = 40
|-46| = 40
46 = 40.
As you can see, the answer already cannot be A because 46 does not equal 40.

doggy · Answer

ohh i see

doggy · Answer

hold on, lemme try to find the answer and i'll ask if i got it right

doggy · Answer

is it C?

joannablackwelder · Answer

That is true, @IParke , but you can only use that method effectively if you are given answer choices. Would you like to know how to solve the problem directly, @doggy?

doggy · Answer

sure, the more i learn the better i suppose

anonymous · Answer

|x – 3| = 40 is the same as saying:

x - 3 = 40
x - 3 = -40

So, solve those two algebra equations.
x = 43
x = -37

So B. {43, -37} is the answer.

anonymous · Answer

@JoannaBlackwelder , you are completely correct! For simplicity's sake, I am a huge fan of substitution. Fast, easy, mostly painless. :)

joannablackwelder · Answer

True, @IParke , it is a great choice, when it is an option. :)