Answer:
58
Step-by-step explanation:
The submarine is below the sea level by 40 meters. Then, it goes up by 12. That means 40-12=28. The submarine goes 30m down again which means 28+30=58
0 it is at ocean level so elevation is zero
Step-by-step explanation:
This is a linear equation in slope intercept form which is

where m is the slope and b is the y intercept.
The equation

Has a slope of -1/3 so this means that the slope will be decreasing. A negative linear equation increases as we go left. and decreases as we go right. The y intercept is 2. So this means the graph must pass through (0,2) and when x=0, y must be 2.
In other words, look for a line that the y values increase as we go left and decrease we go right. Also look for a point (0,2) and make sure the graph pass through it.
The first two negatives cancel out and you're left with positive 4. Now go inside the square root and do the exponent. -4*-4 = 16. Then do the -4*3*1 = -12. Do 16-12 = 4. now the square root of 4 = 2. at the dominator is 2*3 = 6. right now they problem should look like 4+- 2/ 6. from there you split the problem in two. so you have 4+2/6 & 4-2/6 then you solve both problems.
6/6 2/6
1 1/3
1 & 1/3 are your answers. I hope this helped!