Solve log Equations: The Bridge
Convert log form to exponential form to isolate the variable.
Equation
y = 2^x
Graph
Table
| x | y |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 4 |
| 3 | 8 |
| 4 | 16 |
What this lesson covers
What you do
You shape the function y = b^x and watch the graph answer.
Challenges to clear
- With b = 10, the point (3, 1000) appears: log₁₀(1000) = 3.
- Same base: (2, 100) — log₁₀(100) = 2. The bridge works both ways.
- Base 3 now — slide b there.
- Then find the multiplier: x = 4 must read 162. Since 3⁴ = 81, a is 2.
Check yourself
The graph shows y = 10^x. If we start at y=1000 on the vertical axis and move horizontally to the curve, then down to the x-axis, we land on x=3. What does this process define?
Using the same logic, if you start at y=100 on the graph and trace back to the x-axis, what value do you find, and what logarithmic equation does it represent?
- It defines the logarithm: log₁₀(1000) = 3 — correct
- It defines the square root: √1000 = 3
- It defines division: 1000 / 10 = 3
- It defines subtraction: 1000 - 10 = 3
- x=2, representing log₁₀(100) = 2 — correct
- x=3, representing log₁₀(100) = 3
- x=10, representing log₁₀(100) = 10
- x=1, representing log₁₀(100) = 1
Think about it
- log₁₀(1000) = x converts to 10^x = 1000. What is x?