Question

27^x −1 = 9^3x−7 what is X

Answer 1

x is $\frac{11}{3}$

Step-by-step explanation:

Let us revise some rules of exponents

• $(a^{n})(a^{n})=a^{m+n}$
• $\frac{a^{m}}{a^{n}}=a^{m-n}$
• $(a^{m})^{n}=a^{mn}$
• $a^{m}=a^{n}$ , then m = n

∵ $27^{x-1}=9^{3x-7}$

- Factorize 27 and 9

∵ 27 = 3 × 3 × 3

∴ 27 = 3³

∵ 9 = 3 × 3

∴ 9 = 3²

Substitute them in the equation

∴ $(3^{3})^{x-1}=(3^{2})^{3x-7}$

- Use the third rule to simplify each side

∴ $(3)^{3x-3}=(3)^{6x-14}$

- Use the fourth rule

∵ The bases of the two sides are equal

∴ Their exponents are equal

∴ 3x - 3 = 6x - 14

- Subtract 6x from both sides

∴ -3x - 3 = -14

- Add 3 to both sides

∴ -3x = -11

Divide both sides by -3

∴ x = $\frac{11}{3}$

x is $\frac{11}{3}$

Learn more:

You can learn more about equations in brainly.com/question/4934417

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