Answer:
He added the parenthesis to (10+9)
Step-by-step explanation:
The goal here is to find a part of this expression where we can add parentesis so that the value of the equation would be greater than 75
10+9x3-1x2
When we add parentesis to (10+9), we have:
(10+9)x3-1x2
19x3-1x2
= 112
112 is greater than 75.
If we add the parentheses elsewhere like (9x3)
10+(9x3)-1x2
The value would be
10+37-1x2 = 72
And 72 is less than 75
