Solve for \( x \) i \( 3^{x}-3^{x-2}=24 \) if \( 3^{x}+3^{x+2}=10 \) iii \( 2^{x}+2^{x}+2^{x}=96 \) iv \( 12^{x}+12^{x}=288 \) \( 2^{x}+4^{x+1}=80 \)
Real Tutor Solution
Answer
Solution
Reviewed and approved by the UpStudy tutoring team
Bonus Knowledge
To solve for \( x \) in each equation step-by-step: i. Start with \( 3^{x} - 3^{x-2} = 24 \). Rewrite it as \( 3^{x}(1 - \frac{1}{9}) = 24 \), so \( 3^{x} \cdot \frac{8}{9} = 24 \). Thus, \( 3^{x} = 24 \cdot \frac{9}{8} = 27 \). Therefore, \( x = 3 \) since \( 3^{3} = 27 \). ii. For \( 3^{x} + 3^{x+2} = 10 \), rewrite as \( 3^{x} + 9 \cdot 3^{x} = 10 \). Combine like terms: \( 10 \cdot 3^{x} = 10 \) gives \( 3^{x} = 1 \). Thus, \( x = 0 \). iii. The equation \( 2^{x} + 2^{x} + 2^{x} = 96 \) simplifies to \( 3 \cdot 2^{x} = 96 \). Dividing by 3: \( 2^{x} = 32 \) leads to \( x = 5 \) since \( 2^{5} = 32 \). iv. In \( 12^{x} + 12^{x} = 288 \), we rewrite it as \( 2 \cdot 12^{x} = 288 \). Dividing by 2 gives \( 12^{x} = 144 \), which means \( x = 2 \) since \( 12^{2} = 144 \). v. For \( 2^{x} + 4^{x+1} = 80 \), note that \( 4^{x+1} = 4 \cdot 4^{x} = 4 \cdot (2^{2})^{x} = 4 \cdot 2^{2x} \). This rewrites the equation to \( 2^{x} + 4 \cdot 2^{2x} = 80 \). Let \( 2^{x} = y \); then, the equation becomes \( y + 4y^{2} = 80 \). Rearranging gives \( 4y^{2} + y - 80 = 0 \). Using the quadratic formula results in two possible values for \( y \). This can be further simplified for finding \( x \). So the values of \( x \) are: i. \( x = 3 \) ii. \( x = 0 \) iii. \( x = 5 \) iv. \( x = 2 \) v. Solve that quadratic for values of \( x \). Happy solving!