Answer :

naǫ
x - the number

[tex]x+\frac{1}{4}x+\frac{7}{16}x=-13 \frac{1}{2} \\ \frac{16}{16}x+\frac{4}{16}x+\frac{7}{16}x=-\frac{27}{2} \\ \frac{27}{16}x=-\frac{27}{2} \\ x=-\frac{27}{2} \times \frac{16}{27} \\ x=-\frac{1}{2} \times \frac{16}{1} \\ x=-8[/tex]

The number is -8.