Answer:
Equation: 7x - 23 = 25 + x
Solution: x = 8
Step-by-step explanation:
7x - 23 = 25 + x
1. Subtract 25 from both sides:
7x - 23 - 25 = 25 - 25 + x
7x - 48 = x
2. Subtract 7x from both sides to get x on one side:
7x - 7x - 48 = x - 7x
- 48 = -6x
3. Divide both sides by -6 to get x by itself:
8 = x
8 is the solution
Answer:
The number of liters of 25% acid solution = x = 160 liters
The number of liters of 40% acid solution = y = 80 liters
Step-by-step explanation:
Let us represent:
The number of liters of 25% acid solution = x
The number of liters of 40% acid solution = y
Our system of Equations =
x + y = 240 liters....... Equation 1
x = 240 - y
A 25% acid solution must be added to a 40% solution to get 240 liters of 30% acid solution.
25% × x + 40% × y = 240 liters × 30%
0.25x+ 0.4y = 72...... Equation 2
We substitute 240 - y for x in Equation 2
0.25(240 - y)+ 0.4y = 72
60 - 0.25y + 0.4y = 72
Collect like terms
- 0.25y + 0.4y = 72 - 60
0.15y = 12
y = 12/0.15
y = 80 Liters
Solving for x
x = 240 - y
x = 240 liters - 80 Liters
x = 160 liters
Therefore,
The number of liters of 25% acid solution = x = 160 liters
The number of liters of 40% acid solution = y = 80 liters
Answer:
x ≥ −42
Step-by-step explanation:
Let's solve your inequality step-by-step.
x/7≥−6
Step 1: Simplify both sides of the inequality.

Step 2: Multiply both sides by 7.
x ≥ −42
Answer:
y=kx
Step-by-step explanation:
If y is directly proportional to x, then we get the formula y=kx.
Answer:
69.92°F
Step-by-step explanation:
Given:
Initial temperature ( i.e at time, t = 0) = 40°F
Temperature of the room = 70°F
Temperature after 10 minutes ( i.e at time t = 10 ) = 48°F
Now, from Newton's law of cooling
T'(t) = k(A - T(t))
T(t) temperature after time t
T'(t) =
here, A is the room temperature
thus,
= k(70 - T)
or
= kdt
on solving the differential equation, we get
T =
............(1)
Now from the boundary conditions,
i.e at time, t = 0; T = 40°F
we get,
40 = 
or
C = 30
and,
at time, t = 10; T = 48°F
thus,
48 = 
or
k =
or
k = 0.03
Therefore,
for t = 25
from 1 we have
T = 
or
T = 70 - 0.0780
or
T = 69.92°F