Answer:
z = -5
Step-by-step explanation:
Hi there!
We are given the equation 57 = -10z + 7, and we want to solve for z
In order to solve an equation for a variable, we want to isolate that variable on one side; in other words, we want just z on one side of the equation.
So that means that we'll need to get rid of everything else that's also on the right side. That starts with subtracting 7 from both sides:
57 = -10z + 7
-7 -7
_____________
50 = -10z
Now on the right side, there aren't any other extra terms, but remember: we want just z (also written as 1z, with the coefficient of 1), not z written with a coefficient of -10
If you divide a number by itself, the result is 1. For example. [tex]\frac{3}{3}[/tex]= 1. So in order to get a coefficient of 1, let's divide both sides by -10
[tex]\frac{50}{-10} = \frac{-10z}{-10}[/tex]
Divide, and cancel:
The zeros cancel out, leaving the equation as:
[tex]\frac{5}{-1} = \frac{-1z}{-1}[/tex]
Dividing a number by -1 is pretty much the same as multiplying a number by -1; it simply changes the sign of the number
So 5/-1 will become -5, while -1z/-1 will become 1z, or z
Hence:
-5 = z, or written the other way: z = -5
We found z.
Hope this helps!
