3.1.6 Exponent Rules

These problems are usually on the third column, and if you know the basics of exponential rules they are easy to figure out. The rules to remember are as followed:

  • xaxb=xa+bx^a \cdot x^b = x^{a+b}
  • xaxb=xab\frac{x^a}{x^b} = x^{a-b}
  • (xa)b=xab(x^a)^b = x^{ab}

The following are problems concerning each type:

Product Rule: Let 3x=70.13^x = 70.1, then 3x+2=?3^{x+2} = ? Solution: 3x+2=3x32=70.19=630.93^{x+2} = 3^x \cdot 3^2 = 70.1 \cdot 9 = 630.9

Quotient Rule: Let 5x=25^x = 2, represent 5x25^{x-2} as a decimal. Solution: 5x2=5x52=225=.085^{x-2} = \frac{5^x}{5^2} = \frac{2}{25} = .08

Power Rule: Let 4x=1.14^x = 1.1 then 26x=?2^{6x} = ? Solution: 4x=22x=1.126x=(22x)3=1.13=1.3314^x = 2^{2x} = 1.1 \Rightarrow 2^{6x} = (2^{2x})^3 = 1.1^3 = 1.331

The following are some more problems about exponent rules:

Problem Set 3.1.6

6x=346^x = 34, then 6x+2=6^{x+2} =
3x=70.13^x = 70.1, then 3x+2=3^{x+2} =
4x+1=24^{x+1} = 2, then 4x1=4^{x-1} =
6x=726^x = 72, then 6x2=6^{x-2} =
7x=147^x = 14, then 7x2=7^{x-2} =
4x=.1254^x = .125, then 42x=4^{2x} =
8x=178^x = 17, then 82x=8^{2x} =
2x=14.62^x = 14.6, then 2x+1=2^{x+1} =
4x=324^x = 32, then x=x =
9x=1089^x = 108, then 32x+1=3^{2x+1} =
62x=366^{2x} = 36, then 63x=6^{3x} =
8x=2568^x = 256, then x=x =
27x=8127^x = 81, then x=x =
28÷432^8 \div 4^3 has a remainder of
9x=27x+29^x = 27^{x+2}, then x=x =
n4=49n^4 = 49, then n6=n^6 =
16x=16916^x = 169, then 4x=4^x =
53x=252+x5^{3x} = 25^{2+x}, then x=x =
n6=1728n^6 = 1728, then n4=n^4 =
4x÷16x=424^x \div 16^x = 4^{-2}, then x=x =
68÷86^8 \div 8 has a remainder of
a43×a34=an12,n=\sqrt[3]{a^4} \times \sqrt[4]{a^3} = \sqrt[12]{a^n}, n =