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2^x-2 + 2^3-x = 3
Solve for x​

User Valera
by
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1 Answer

4 votes

Answer:

The value of x is 3 or 2.

Explanation:

Given equation is 2^(x-2) + 2^(3-x) = 3

On applying exponents rule a^(x-y) = a^x÷a^y

Where, a = 2, x = x and y = -2

  • a = 2, x = 3 and y = -x

So, using this, we get

⇛{(2^x/2²) + (2³/2^x)} = 3

⇛{(2^x/2*2) + {(2*2*2)/2^x}] = 3

⇛[(2^x)/4} + {(4*2)/2^x}] = 3

⇛[(2^x)/4} + {8/(2^x)}] = 3

Let assume that 2^x = y

So, above equation can be rewritten as

⇛{(y/4) + (8/y)} = 3

⇛{(y²+32)/4y} = 3

⇛{(y²+32)/4y} = (3/1)

On applying cross multiplication then

⇛1(y²+32) = 3(4y)

Multipy the number outside of the brackets with numbers and variables on the brackets on both LHS and RHS.

⇛y²+32 = 12y

⇛y²-12y + 32 = 0

By splitting the middle term, we get

⇛y² - 8y - 4y + 32 = 0

⇛y(y-8) - 4(y-8) = 0

⇛(y-8)(y-4) = 0

➝ y = 8 or y = 4

➝ 2^x = 8 or 2^x = 4

➝ 2^x = 2³ or 2^x = 2²

Therefore, x = 3 or x = 2

Answer: The value of x is 3 or 2.

VERIFICATION:

•If x = 3 the equation is

2^(x-2) + 2^(3-x) = 3

Substitute the value of x = 3 in equation

⇛2^(3-2) + 2^(3-3) = 3

⇛2¹ + 2⁰ = 3

⇛2 + 1 = 3

⇛3 = 3

LHS = RHS

•If x = 2 then the equation is

2^(x-2) + 2^(3-x) = 3

Substitute the value of x = 2 in equation

⇛2^(2-2) + 2^(3-2) = 3

⇛2^0 + 2^1 = 3

⇛1 + 2 = 3

⇛3 = 3

LHS = RHS

Hence, verified.

Please let me know if you have any other questions.

User Kacperito
by
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