List the elements of the set $\{X \in \mathbb Z \mid 4X^2 +11X = 0\}$

Question

I don't get this maths equation

Can anybody explain it ? Thanks

List the elements of the following set: $A=\{X \in \mathbb Z \mid 4X^2 +11X = 0\}$.

If I read symbols correctly, it asks to find the integer roots of $4x^2+11x = (4x+11)x$... — Milly, Oct 20 '14 at 16:58
@Milly Not exactly, since the roots should be relative integers. — Martigan, Oct 20 '14 at 16:59
By "integer" I meant $\mathbb{Z}$, not $\mathbb{N}$ (natural numbers). — Milly, Oct 20 '14 at 17:01

score 4 · Answer 1 · 2014-10-20T17:41:02.750

4

This means that $A$ is the set of all integers $x$ for which $4x^2 + 11x = 0$.

When you solve the equation $4x^2 + 11x = 0$ you will find that only $x = 0$ and $x = -\frac{11}{4}$ satisfy it. Since you're only looking for $x \in \mathbb{Z}$, you can conclude that $A = \{0\}$.

edited Oct 20 '14 at 17:41

answered Oct 20 '14 at 16:58

List the elements of the set $\{X \in \mathbb Z \mid 4X^2 +11X = 0\}$

1 Answers1