2^{a+5}+2^{a+4}+2^{a+3}=28

解答

2^{a + 5} + 2^{a + 4} + 2^{a + 3} = 28

a = - 1

求解步骤

2^{a + 5} + 2^{a + 4} + 2^{a + 3} = 28

因式分解

2^{a + 5} + 2^{a + 4} + 2^{a + 3} : 7 \cdot 2^{a + 3}

7 \cdot 2^{a + 3} = 28

两边除以

7

2^{a + 3} = 4

使用指数运算法则

a + 3 = 2

解

a + 3 = 2 : a = - 1

a = - 1

100 = 96.87 e^{x}

x^{x} = 2

1 6^{x - 4} = 25 6^{3 x + 3}

7^{2 x - 1} = 49 \cdot 7^{x - 1}

3^{2 x} - 5 (3)^{x} + 4 = 0