Answer:
y=-1
Step-by-step explanation:
-5y+8=-3y+10
-5y-(-3y)+8=10
-5y+3y=10-8
-2y=2
y=2/-2
y=-1
Yes, Bobby will have enough money if he saves for 9 weeks. You can find this through either substituting w for 9 in the equation, or solving the equation itself.
Substituting:

Substitute w for 9.

Simplify.

Solve.
255 is greater than 250, so yes, he will have enough money saved.
Solving the equation:

Original Equation

Subtract 30 from both sides.

Divide both sides by 25.
The number of weeks he needs is 8.8. When rounding it up, you get 9.
4.8y - 6.9 = 3.18
4.8y= 3.18 + 6.9 (I added 6.9 to both sides)
4.8 y = 10.08 (I added 3.18 by 6.9)
y = 2.1 (I divided 4.8)
Hope this helps!!