20
Start with
[tex]\dfrac{x}{4} + 10 = \dfrac{3}{4}[/tex]
Multiply both sides by 4:
[tex]x+40=3[/tex]
Subtract 40 from both sides:
[tex]x = -37[/tex]
21
If the absolute value of something equals 12, then that something is either 12 or -12: the possibilities are
[tex]x+8=12 \iff x=4[/tex]
or
[tex]x+8=-12 \iff x=-20[/tex]
22
You can isolate the absolute value
[tex]-3|x-4|+2=-7 \iff -3|x - 4|=-9 \iff |x - 4|=3[/tex]
And proceed as before.
23
Distribute the 16:
[tex]16x-32-x+3=29 \iff 15x-29=29 \iff 15x=58 \iff x = \dfrac{58}{15}[/tex]
24
Multiply both sides by 6/5:
[tex]2x-8=54 \iff 2x=62 \iff x=31[/tex]
25
Start with
[tex]F=\dfrac{9}{5}C+32[/tex]
Subtract 32 from both sides
[tex]F-32=\dfrac{9}{5}C[/tex]
Multiply both sides by 5/9
[tex]\dfrac{5}{9}(F-32)=C[/tex]
