Answer:
u = -2
Step-by-step explanation:
Group
[tex]6u+9u+18=-12[/tex]
Add similar elements in the equation
[tex]15u+18=-12[/tex]
Subtract 18 from all sides
[tex]15u+18-18=-12-18[/tex]
Simplify this
[tex]15u=-30[/tex]
Divide all sides by 15
[tex]\frac{15u}{15}=\frac{-30}{15}[/tex]
Divide 15 by 15, removing u
[tex]\frac{15}{15} = u[/tex]
Transform [tex]\frac{-30}{15}[/tex] by using the fraction rule.
[tex]-\frac{30}{15}[/tex]
Divide 30 by 15.
[tex]\frac{30}{15} = 2[/tex]
Thus,
u = -2
