Question

plz solve this question
(exponential equations)
plz... answer my questions first.​

Answer 1

Answer:

vii)

$3 {}^{x + 2} + 3 {}^{x + 4} = 810$

$3 {}^{x} .3 {}^{2} + 3 {}^{x} .3 {}^{4} = 810$

$3 {}^{x} (3 {}^{2} + 3 {}^{4} ) = 810$

$3 {}^{x} (9 + 81) = 810$

$3 {}^{x} = 9$

$3 {}^{x} = 3 {}^{2}$

$x = 2$

Answer 2

Answer:

(3) (1,2)

Step-by-step explanation:

$(7) \\ {3}^{x + 2} + {3}^{x + 4} = 810 \\ \\ = > {3}^{2} \times {3}^{x} + {3}^{4} \times {3}^{x} = 810 \\ \\ = > 9 \times {3}^{x} + 81 \times {3}^{x} = 810 \\ \\ = > 90 \times {3}^{x} = 810 \\ \\ = > {3}^{x} = 9 \\ \\ = > {3}^{x} = {3}^{3} \\ \\ = > x = 3 \\ \\ \\ \\ (10) \\ {9}^{x} - 4 \times {3}^{x + 1} + 27 = 0 \\ \\ {( {3}^{2}) }^{x} - 4 \times 3 \times {3}^{x} + {3}^{3} = 0 \\ \\ ( {3}^{x} ) {}^{2} - 12 \times {3}^{x} + 27 = 0 \\ \\ {( {3}^{x} )}^{2} - 9 \times {3}^{x} - 3 \times {3}^{x} + 27 = 0 \\ \\ {3}^{x} ( {3}^{x} - 9) - 3( {3}^{x} - 9) = 0 \\ \\ ( {3}^{x} - {3}^{2} )( {3}^{x} - {3}^{1} ) = 0 \\ \\ = > {3}^{x} = {3}^{2} \\ = > x = 2 \\ \\ = > {3}^{x} = {3}^{1} \\ = > x = 1 \\ \\ \\ \\ formulae \\ \\ if \: {a}^{x} = {a}^{y} \\ = > x = y \\ \\ ({a}^{x}) {}^{y} = {a}^{xy}$

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