Answer:
x=-3
Step-by-step explanation:

x+3=0
-3 -3
x= -3
opposite of addition would be subtraction. since your trying to solve for x You want to get x alone and you subtract by 3 on both sides which would cancel the 3 on the left, leaving:

if you follow the same process on all of them you come to the conclusion that only -3 is a zero in the options listed.
NOTE: When you become more experienced whenever you see expressions like that you'll come to realize that the zero is the opposite sign of the number if it's just x- or x+ a number.
example:

it'll be the opposite sign so since it's a negative the zero of that would be positive 40.
hope this helps!
Answer:
x=10, 120
Step-by-step explanation:
5x+70=7x+50
-5x -5x
70=2x+50
-50 -50
20=2x
---- ----
2 2
10=x
5(10)+70=7(10)+50
Answer:
b. 10a³ - 11a - 3
Step-by-step explanation:
1. Expand 3(a³ - 2a - 5)
= 3a³ - 6a - 15
2. Add 7a³ - 5a + 12 and 3a³ - 6a - 15
7a³ + 3a³ = 10a³
-5a + -6a = -11a
12 + -15 = -3
3. Answer: b. 10a³ - 11a - 3
Answer:
x≥ -4
Step-by-step explanation:
9 + 9(x + 7)≥ 36
Subtract 9 from each side
9 -9+ 9(x + 7) ≥ 36-9
9(x + 7) ≥ 27
Divide each side by 9
9/9(x + 7) ≥ 27/9
x+7≥ 3
Subtract 7 from each side
x+7-7 ≥ 3-7
x≥ -4