Algebra Question. (involves linear equations)?

Question

Word problem:
Geothermal energy is createdwherever water comes into contact with heated underground rocks. The underground temp. of rocks varies with their depth below the surface. The temp. (t) in degrees celsius is estimated by the function:
t(d)=35d+20
where d is the depth in kilometers of the rocks
A- Graph the linear equation [y'all don't have to]
B-Find the temp. of the rocks at a depth of 3 kilometers [ I think it's 125 or 375?]
C-Is the function discrete or continous? Explain your reasoning
D-Find the depth if the temp. of the rocks is 195 degrees Celsius

Answer 1

B- correct 35x3=105+20=125 degrees
C. i would say discrete since the graph must have an end since the depth of the earth is finite.
D 195=35d+20 minus 20 from both sides
175=35d divide both sides by 35 and ill let you do the rest

Answer 2

The temperature of the rocks at 3 km is found by substituting "3" for "d" in the equation:
35(3) + 20 = 105 + 20 = 125 degrees Celsius

The function is CONTINUOUS because distance is continuous. You can also find the temperature at 3.02756km or at any other distance. The function is, however, finite at both ends. It starts at the earth's surface and would end either at the earth's center if you measure distance from the starting point at the surface, or else you would get a mirror image of your line up to the center as you proceed to the surface on the other side of the world. That would be obvious since your true depth would now be measured from the other side.

If the rock temperature is 195 C, we would work the equation backwards to find the depth.
195 = 35d + 20
Subtract 20 from both sides to get:
175 = 35d
divide both sides by 35:
5 = d
You would be at a depth of 5 km

Answer 3

look at your x-y graph. look on the y -axis. The equation for the y-axis may well be x = 0 Do you spot that? the fee alongside the y-axis for "x" is often 0. positioned a pencil over the y-axis and contact it x = 0 Now, flow the pencil to x = 5 and stay parallel to the y -axis Now each fee alongside the pencil for "x" may well be 5 the equation is x = 5 you need to to an analogous factor with y=0. right here you may lay the pencil alongside the x-axis. flow it UP 3 units for y = 3