Start by expanding the left hand side:
[tex] 4 \times 0.5 z + 4 \times (-10) = 10z+4 [/tex]
which leads to
[tex] 2z -40 = 10z+4 [/tex]
Now we want to move all terms involving the variable to the left hand side, and all constant terms on the right hand side:
[tex] 2z-10z = 4+40 [/tex]
Simplify both sides by summing like terms:
[tex] -8z = 44 [/tex]
Divide both sides by -8 to solve for x:
[tex] z = \cfrac{44}{-8} = -\cfrac{22}{4} = -\cfrac{11}{2} = -5.5 [/tex]
