So we have the equation:

Then we need to multiply by 4 on both sides to get rid of the denominator on the left:

Then we subtract 9 on both sides to solve for z:

Therefore the answer is z = -0.6.
175 students walk to school. 7+5=12 and 420 divided by 12 is 35. I checked how I did it was correct because of 5*35+7*35=420. Then I found the product of 5*35 which is 175.
Answer:
The numbers are 17 and 5
Step-by-step explanation:
x + y = 22
x - y = 12
Add y to both sides of the equation
x = 12 + y
Substitute new value for x into first equation
12 + y + y = 22
Add the y's
12 + 2y = 22
Subtract 12 from both sides
2y = 10
y = 5
22 - 5 = 17
The numbers are 17 and 5
Hope this helps :)