What is the square of X + 7x + 12 + (0.5)

What is the square of X + 7x + 12 + (0.5)

Original formula = x & sup2; + 7x + 49 / 4
=(x+7/2)²

How do five nines equal 21,
Intelligence questions:
9 9 9 9 9＝21
Use '+', '-', '×', '△' or brackets
Ha ha, I have thought of both methods. I don't know if there is a better plan. It seems that there is no more!

It's good upstairs. It's right
I don't know if it's OK
The square root of 9 is 3
9+9 ＝ 18
9-9 ＝ 0
3+18+0＝21

What's in the middle of five nines and it's 21 in the end
9 9 9 9 9=21

Wait for the master

2 3 4 5 6 7 8 9 can only use the plus and minus sign, how can it be equal to 10

2+3+4+5+6+7-8-9=10

1,2,3,4,5,6,7,8,9 with appropriate addition and subtraction sign, the result is 9

1+2-3+4+5+6-7-8+9=9

If 5 * 2 = 11, 6 * 3 = 21, 7 * 4 = 34, then 1 * 9 + 2 * 9 + 3 * 9 + +9*9=______ ．

1*9+2*9+3*9+… +9*9，=（1+2+3+4+5+6+7+8+9）+（2+3+4+5+6+7+8+9+10）+（3+4+5+… +11）+… +（9+10+11+12+… +17），=45+（45+9）+（45+2×9）+（45+3×9）+… +(45 + 8 × 9), = 45 × 9 + (9 + 72) × 8 △ 2, = 405 + 324, = 729

5 * 2 = 5 + 6 = 11, 6 * 3 = 6 + 7 + 8 = 21, then what is 1 * 9 = 2 * 9 + 3 * 9 + 4 * 9 + 5 * 9

=(1+2+3+4+5+6+7+8+9)+(2+3+4+5+6+7+8+9+10)+(3+4+5+6+7+8+9+10+11)+(4+5+6+7+8+9+10+11+12)+(5+6+7+8+9+10+11+12+13)
=45+54+63+72+81
=315

If 5 * 2 = 11, 6 * 3 = 21, 7 * 4 = 34, then 1 * 9 + 2 * 9 + 3 * 9 + +9*9=______ ．

1*9+2*9+3*9+… +9*9，=（1+2+3+4+5+6+7+8+9）+（2+3+4+5+6+7+8+9+10）+（3+4+5+… +11）+… +（9+10+11+12+… +17），=45+（45+9）+（45+2×9）+（45+3×9）+… +（45+8×9），=45×9+（9+72）×8÷2，=405+324，=729．...

What is the maximum value of the function y = x * (3-2x) (x is greater than or equal to 0 and less than or equal to 1)

The vertex formula of quadratic function (x ^ 2 is the square of x)
Let y = f (x) = - 2x ^ 2 + 3x = - 2 [(x-3 / 4) ^ 2] + 9 / 8 (0)

When | x + 1 | ≤ 6, the maximum value of the function y = x | x | - 2x + 1 is______ ．

When 0 ≤ x ≤ 5, y = x2-2x + 1, that is, y = (x-1) 2, then y max = (5-1) 2 = 16; when - 7 ≤ x < 0, y = - x2-2x + 1, that is, y = 2 - (x + 1) 2, then y max = 2. Therefore, when - 7 ≤ x ≤ 5, y max = 16