Answer:
PE = 83 and Science = 71
Step-by-step explanation:
let P represent PE and S represent Science with P > S, then
P + S = 154 → (1)
P - S = 12 → (2)
Adding the 2 equations term by term eliminates S
2P = 166 ( divide both sides by 2 )
P = 83
Substitute P = 83 into (1)
83 + S = 154 ( subtract 83 from both sides )
S = 71
Hence PE mark = 83 and Science mark = 71
Answer:
(a) k = C + 273.15, F = 1.8(k - 273.15) + 32
(b) k = 296.15
(c) 25 celcius is greater than 300 kelvis.
Step-by-step explanation:
(a) one equation would be to solve for k instead of c, and another related equation could be from kelvin to Farenheit.
C = k - 273.15
C + 273.15 = k
k = C + 273.15
F = 1.8(k - 273.15) + 32
(b) for this one you have to substitute in the previous equation and solve for k.
23 = k - 273.15
k = 23 + 273.15
k = 296.15
(c) you have to convert either kelvins to celcius or celcius to kelvins.
C = k - 273.15
C = 300 - 273.15
C = 26.85
So 25 celcius is greater than 300 kelvis.
Answer:

Step-by-step explanation:

Let's create a table of the values.

4x + 2y = 5y + 7
4x - 3y = 7
4x - 3y = 7
8x + 3y = 41
----------------add
12x = 48
x = 48/12
x = 4
8x + 3y = 41
8(4) + 3y = 41
32 + 3y = 41
3y = 41 - 32
3y = 9
y = 9/3
y = 3
solution is (4,3)