Question

If 3|x|+5ly|=8 and 7|x|-3|y|=48, then the value of

x+y is?​

Answer 1

Step-by-step explanation:

Think about this:

Is 2x + 7 = 0 same as -2x + 7 = 0?

You know that these two are different equations and yield different values of x. x can be negative/positive.

On the other hand, how do you solve something like this: 2|x| + 7 = 0

You need the value of x, not of |x|. How will you get the value of x?

You will use the definition of |x|

|x| = x if x >= 0

|x| = -x if x < 0

So you take 2 cases:

Case 1:

x >= 0 so |x| = x

2|x| + 7 = 0 => 2x + 7 = 0

x = -7/2 (this doesn't work since x must not be negative)

Case 2:

x < 0 so |x| = -x

2|x| + 7 = 0 => 2(-x) + 7 = 0

x = 7/2 (this doesn't work either since x must be negative)

So there is no value of x that satisfies 2|x| + 7 = 0

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Answer 2

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Refer to the attachment

Hope it will help you