Log Equations Lesson

Logarithmic Equations

Let's work this one together!

You CANNOT have a negative log.

Make sure you substitute your answer back in to check if it's a negative solution!

Multiple Choice

$$\log_2\left(1-4n\right)=\log_2\left(2n+43\right)$$  

• n=7

• n=-7

• n=21

• n=-21

Multiple Choice

$$\log_6\left(6-3w\right)=\log_6\left(-2w\right)$$  

• NO SOLUTION

• W=-6

• W=5/6

• W=6/5

Multiple Choice

$$\log\left(y+5\right)+\log4=\log72$$  

• y=63

• no solution

• y=-13

• y=13

Let's do this one together!

Multiple Choice

$$\log_3\left(4x+8\right)-7=-3$$  

• $$x=\frac{73}{4}$$  

• no solution

• $$x=1$$  

• $$x=-1$$  

Multiple Choice

log(2x)+log(x-5)=2

You will get two answers. Substitute back in to see which is the correct answer!

• x=10

• x=5

• x=10

• x=-5

Multiple Choice

2logx-log4=2

• No solution

• x=20

• x=-20

• $$x=\pm20$$