In the equation 3 times () - 2 times () = 40, fill in a number in the two brackets, so that the two numbers are opposite to each other, and the equation holds, then what is the number filled in the first bracket?

In the equation 3 times () - 2 times () = 40, fill in a number in the two brackets, so that the two numbers are opposite to each other, and the equation holds, then what is the number filled in the first bracket?

The number of brackets is: the first bracket is 8, and the second bracket is - 8
Let the number of the first bracket be a, then the number of the second bracket is - A
Nested formula: 3 x a - 2 x (- a) = 40
3a+2a=40
5a = 40
a = 8

In the equation 3 times () + 5 times () = 7, fill in a number in two brackets respectively, and the sum of the two numbers filled in is 1

3 * 1.5 + 5 * 0.5 full of friends

Add parentheses, brackets and braces to the formula 1 + 2x3 + 4x5 + 6x7 + 8x9 = 1005 to make the formula hold

(1+2)x[3+4x(5+6)x7]+8x9=1005
That's all,

Add brackets to the formula 1 + 2x3 + 4x5 + 6x7 + 8x9 = 1717 to make the formula hold

Unfortunately, that's all I think about
1+2x3+[(4x5+6)x7+8]x9=1717