How do you know if an absolute value equation has no solution?
Absolute value functions are always greater than or equal to zero.
Answer: There are 0 solutions to the equation |-5 - 4x| + 9 = -40
There is one major red flag of an equation with an absolute value that has no solution.
An absolute value expression can never be less than zero. That is a fully reduced absolute value expression must be greater than or equal to zero.
If on simplifying an absolute value expression, the value on the other side of the equation has a negative sign i.e. it is a negative number then it has no solutions.
Lets verify this with an example,
⇒ |-5 - 4x| + 9 = -40
First, we have to isolate the absolute value expression, so we'll subtract 9 from both sides.
⇒ |-5 - 4x| = -49
We observe that LHS is positive while RHS is negative, which contradicts.