20
Start with
![(x)/(4) + 10 = (3)/(4)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/e17nobwjlxo2r0a2oscfkfsa0cb431xa2h.png)
Multiply both sides by 4:
![x+40=3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zciezslgatyqdp8jq3mrdk8g9qzl8wex4h.png)
Subtract 40 from both sides:
![x = -37](https://img.qammunity.org/2020/formulas/mathematics/middle-school/vkf38g5879gliwe3ebt5je2y8q91b1efjv.png)
21
If the absolute value of something equals 12, then that something is either 12 or -12: the possibilities are
![x+8=12 \iff x=4](https://img.qammunity.org/2020/formulas/mathematics/middle-school/bc4wrhokghl2xk5h7ivdjh9fjqcvjhnn47.png)
or
![x+8=-12 \iff x=-20](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8qtbqb3e2kdhg1sxzlqeicidq6nrvglvoy.png)
22
You can isolate the absolute value
![-3|x-4|+2=-7 \iff -3|x - 4|=-9 \iff |x - 4|=3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2rhsudangpiub6sbn0gycah1gcb6uasiaa.png)
And proceed as before.
23
Distribute the 16:
![16x-32-x+3=29 \iff 15x-29=29 \iff 15x=58 \iff x = (58)/(15)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/556nbzhwu9toircyhi3386a6hucz5feqr6.png)
24
Multiply both sides by 6/5:
![2x-8=54 \iff 2x=62 \iff x=31](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7nyr0rimnlh72rvylf0r2zews4cqecei1u.png)
25
Start with
![F=(9)/(5)C+32](https://img.qammunity.org/2020/formulas/mathematics/middle-school/no9tzsfncwzdx5k7rl6ljzbgegaq4mfxkz.png)
Subtract 32 from both sides
![F-32=(9)/(5)C](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ee6s88u6itvhibguokszbihm9xrm7okfdw.png)
Multiply both sides by 5/9
![(5)/(9)(F-32)=C](https://img.qammunity.org/2020/formulas/mathematics/middle-school/gv0bya3mvdtyua0di4jcucebbgq2090gpm.png)