it would be -1
15 +26+9+12
25x (square) plus 40 plus 15 equals 680.
-55
40
-26
40
40 + 15% = 40 x (1 + (15/100)) = 40 x 1.15 = 46
It is: 40/10 = 15/100 = 4.15
-41
25+15=40+9=49
40
It depends where you want the parentheses: 15 + (26 x 10) = 275 (15 + 26) x 10 = 410