Question

Is the equation 3+z=-19
true, false or open?

Answer 1

Any ideas?

Answer 2

No i'm stuck

Answer 3

hint: when they say "is the equation true" they mean "Is it ALWAYS true for ALL values of z?"

Answer 4

So is 3+z=-19 always true for all values of z?

Answer 5

no?

Answer 6

good, there's only one value of z that works, do you know what it is?

Answer 7

This is known as "Conditionally True".

Answer 8

subtract 3 from both sides to get

3+z=-19

3+z-3=-19-3

z = -22

So it's only true when z = -22. This means that it's neither 100% true nor 100% false. So it's an open statement or sentence.