Answer:
7 2/3 minutes
Step-by-step explanation:
We can write this equation in y = mx+b form
where m = 3 ft/min and b = -105 ft
x is the number of minutes and y is the depth
y = 3 * x -105
We want to find when y = -82
-82 = 3x -105
Add 105 to each side
-82+105 = 3x-105+105
23=3x
Divide by 3
23/3 = 3x/3
23/3=x
Changing into a mixed number
3 goes into 23 7 times with 2 left over
7 2/3 minutes
<span> Coefficients are numbers used to multiply a variable.
IN this case, the coefficients are -8, 12 and 5.
</span>
Y = 2y + 9. A = y, 2 means multiply yhe variable y two times, and u just add 9. Btw y = -9
We are have a system of equations with 2 variables, x and y
Equation 1: -3x-3y = 3
Equation 2: y = -5x-17
For equation 1, the y is by itself on one side of the equation, so it is really easily to substitute it into equation 2. In general, to solve for system of equations, you either do elimination or substitution. You just have to find which is easier for this situation.
By substituting y for -5x-17 in equation 1, there is only 1 variable which we can solve for.
-3x-(-5x-17) = 3
Distribute negative sign to (-5x-17) Avoid the common error of forgetting!
-3x+5x+17 = 3
Combine like terms- same variables are like terms (ex. 4x and 29x) and all constants are like terms (ex. 7 and 189 )
2x+17 = 3
Subtract 17 from both sides so all the variables are on one side and the constants on the other
2x = -14
Divide both sides by 2 to isolate the x
x = -7
We now know that x = -7 so we need to plug it into an equation to solve for y
Equation 2: y = -5x-17
y = -5 (-7) -17
y = 18
Now we know that x = -7 and y = 8
We can write it as (-7, 8)
