Answer:
1. -21
2. 0
3.
![-(5)/(6)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/s6b6qk7tc1w0h8n2zcvbmumj1xze3n6a2e.png)
Explanation:
1. 18 =
![-(6)/(7) h](https://img.qammunity.org/2023/formulas/mathematics/middle-school/4smhqya5da6srqyx1lgxjk7efd66rx4wi4.png)
multiply both sides by the reciprocal of -6/7.
18 =
![-(6)/(7) h](https://img.qammunity.org/2023/formulas/mathematics/middle-school/4smhqya5da6srqyx1lgxjk7efd66rx4wi4.png)
![(-(7)/(6) )](https://img.qammunity.org/2023/formulas/mathematics/middle-school/o5hmffcjxlbv5lc6q0bic106l77iewded9.png)
-21 = h
-------------------
2.
![-(3)/(4) x=(21)/(8) x](https://img.qammunity.org/2023/formulas/mathematics/middle-school/ffy3gpv2boewv9ops7nxygzytnjph39h8r.png)
find the LCM of both fractions.
LCM = 8
multiply both fractions by the LCM
![-(3)/(4) x(8)=(21)/(8) x(8)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/ct5en1xf7l5d3lvwwko9x9arlzv80zslio.png)
-6x = 21x
subtract 21x from both sides
-6x-21x = 21x-21x
-27x = 0
isolate x
-27x/-27 = 0
x = 0
-------------------
3.
![-(1)/(2) z=(5)/(12)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/5us7pou0dcx4a0mreh4scsqbakvhfyvgyz.png)
multiply both sides by the reciprocal of -1/2.
![-(1)/(2) z(-2)=(5)/(12)(-2)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/fzhfpfmrrldkz2iv9cmusrd0ycy2s2cphs.png)
z =
![-(5)/(6)](https://img.qammunity.org/2023/formulas/mathematics/middle-school/s6b6qk7tc1w0h8n2zcvbmumj1xze3n6a2e.png)
hope this helps :)