Okay, so on number one I have no idea. I keep getting 20 because 14 - (-3)2 = 14- (-6) which is really 14 + 6=20.
Number 2 is r+15=61
Number 3 I didn't get any of those answers because you have to solve what is in the parenthesis first so3*5= 15+1=16 then you multiply that by two giving you 16*2=32 and 42-32=10
To solve this we need to use this formula:


So if we want to know the common solution(s) to a system of 2 equations, So we can just set both equations equal to each other and solve for the x value(s). That’s where I start below;
2x^2-13x+21 = 2x^2+9x-56
2x^2 cancels out and moving everything to one side and anything with an x variable to the other side we have then;
-22x=-77
22x=77 by cancelling the negative signs
x=77/22 therefore x=7/2 or 3.5
Hope this helps you. Any questions please ask.
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