I won't answer them all for you (don't want to cheat - need to learn something).
But for the first one given:
<span>-2x-9y=-25
-4x-9y=-23
you set up either x or y (which ever one you want to eliminate) so that one of them cancels.
So this one is easy - you just have to multiply an entire row by negative (doesn't matter which one) - so that the y's will be + and - 
Since they're both 9 and they're subracting NOW - you can eliminate the y value. Now add/subtract the x's. So it'd be -2 or 2 depending on how you eliminated y. Then add the number outside of the = sign. Now just solve for x. After that plug in whatever you got for x into both of the rows. Then find the y value.
Hopefully this wasn't confusing -- reply if it is and I will try to simplify. I can give you contact if you need help with the rest 
Good luck!</span>
        
             
        
        
        
Answer:
- Cost of fish = Php. 60, amount of fish = x kg
- Cost of chicken = Php. 120, amount of chicken = y kg
- Budget = at most Php. 1200
a) <u>Required inequality (not a system as only one condition is given):</u>
<u>Simplified:</u>
- <em>The graph is attached</em>
b) <u>Verify ordered pair (10, 7):</u>
False inequality, so this pair is out of solution set
 
        
             
        
        
        
Answer:
3/7
Step-by-step explanation:
The number of possible results are;
1, 2 , 3 , 4 , 5, 6 , 7 = 7 
odd numbers here are;
1, 3 , 5 and 7
non-odd numbers are 2, 4 and 6 
So the section not labeled with an odd number is 3
Hence the probability here is that;
3/7