Answer:
[tex] \boxed{ \sf{ \bold{1. \: \: \: x = 5}}}[/tex]
[tex] \boxed{ \sf{ \bold{2. \: \: x = 6}}}[/tex]
[tex] \boxed{ \bold{ \sf{3. \: \: x = 21}}}[/tex]
Step-by-step explanation:
1. [tex] \sf{3x + 6 = 21}[/tex]
Move constant to right hand side and change its sign
⇒[tex] \sf{3x = 21 - 6}[/tex]
Subtract 6 from 21
⇒[tex] \sf{3x = 15}[/tex]
Divide both sides of the equation by 3
⇒[tex] \sf{ \frac{3x}{3} = \frac{15}{3} }[/tex]
Calculate
⇒[tex] \sf{x = 5}[/tex]
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2. [tex] \sf{33 = 7x - 9 }[/tex]
Swap the sides of the equation
⇒[tex] \sf{7x - 9 = 33}[/tex]
Move constant to right hand side and change it's sign
⇒[tex] \sf{7x = 33 + 9}[/tex]
Add the numbers
⇒[tex] \sf{7x = 42}[/tex]
Divide both sides of the equation by 7
⇒[tex] \sf{ \frac{7x}{7} = \frac{42}{7} }[/tex]
Calculate
⇒[tex] \sf{x = 6}[/tex]
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3. [tex] \sf{28 = 7 + x}[/tex]
Swap the sides of the equation
⇒[tex] \sf{7 + x = 28}[/tex]
Move constant to right hand side and change it's sign
⇒[tex] \sf{x = 28 - 7}[/tex]
Subtract 7 from 28
⇒[tex] \sf{x = 21}[/tex]
Hope I helped!
Best regards!!
