Solve the equation without using a calculator.
-
B) 3
D) -3

Name: Solve the equation without using a calculator. - B) 3 D) -3
Brand: Quizplus
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Question

Solve the equation without using a calculator.
-
B) 3 
D) -3

Quizplus · Accepted Answer

Rearrange the given equation as $8\cdot 9^x=16\cdot 3^x$. Divide both sides by $3^x$ to get $8\left(\frac93\right)^x=16$. Simplify to $2\cdot 3^x=16$, and divide both sides by $2$ to obtain $3^x=8$. Therefore, $x=\boxed{3}$. The equation can be simplified as follows:
$(1+2+3+...+7)-4-4=28-4-4=20$
So the answer is 3.

Solve the Equation Without Using a Calculator