z/.07
x = 7z/100
z+7
z - 7
-7
(2z - 7)(z + 4)
It is an expression in three variables, x, y and z.
(3z + 5)(z -7)
The equation z-19 time 34 is a verbal sentence. This a math problem.
34 percent of z is 0.34z
z + 8 - 2 is an expression, not an equation. An expression cannot be solved. At best, you can simplify it to z + 6.
It is: z-8
"decreased by" means "minus" 12 decreased by z means 12 - z It really is that simple.