Question

Tìm x:

\(\left(x^2-1\right)^2=9\)

\(12:\left\{390:\left[5.10^2-\left(5^3+x.7^2\right)\right]\right\}=4\)

\(5^3.\left(3x+2\right):13=10^3:\left(13^5:13^4\right)\)

Giúp mik vs nha m.n!>.<

Answer 1

(x²-1)²=9

=> x²-1 = 3 

x² = 3+1

x² = 4

=> x² = 4 = 2² ( x²=2² )

<=> x = 2

12:{390:[5.10²-(5³+x.7²)]} = 4

390:[5.10²-(5³+x.7²)] = 12:4

390:[5.10²-(5³+x.7²)] = 3

5.10²-(5³+x.7²) = 390 : 3

5.10²-(5³+x.7²) = 130

=> 500-(125+x+49)=130

125+x+49 = 500-130

125+x+49 = 370

125+x = 370-49

125+x = 321

x = 321-125

x = 106

5³(3x+2):13=10³:(13⁵:13⁴)

5³(3x+2):13=10³:13

5³(3x+2):13= 1000/13

125(3x+2):13 = 1000/13

125(3x+2) = 1000/13 . 13

125(3x+2) = 1000

3x+2 = 1000:125

3x+2 = 8

3x = 8-2

3x = 6

x = 6:3

x = 2