49-apex
3
9
82+8 = 72
9 needs to be added to complete the square. When squaring (x + n), the result is x2 + 2nx + n2. We have +10x, so n must be 10/2 = 5. Thus: (x + 5)2 = x2 +10x + 25 = x2 +10x + 14 + 9 So 9 needs to be added to complete the square, giving: x2 +10x + 14 = (x + 5)2 - 9
-7
3
9
102 +10=110
82+8 = 72
-3
144
9 needs to be added to complete the square. When squaring (x + n), the result is x2 + 2nx + n2. We have +10x, so n must be 10/2 = 5. Thus: (x + 5)2 = x2 +10x + 25 = x2 +10x + 14 + 9 So 9 needs to be added to complete the square, giving: x2 +10x + 14 = (x + 5)2 - 9
-7
49/4 or 12.25
1 is the number you are looking for.1 + 12 = 1 + 1 = 2.QED
Adding 100 completes the square. { I wonder why you want to complete the square when the expression already factors as x(x-20) }.
To complete the square for the expression ( x^2 + 8x ), first take half of the coefficient of ( x ) (which is 8), square it, and add it. Half of 8 is 4, and squaring it gives ( 4^2 = 16 ). Therefore, the number that must be added to ( x^2 + 8x ) to complete the square is 16. Thus, the completed square form is ( (x + 4)^2 ).