Question

bài 1:tìm x

a,5^2x-3-2.5²=5².3

Answer 1

\(a,5^{2x-3}-2.5^2=5^2.3\)

\(5^{2x-3}-2.5^2=25.3\)

\(5^{2x-3}-2.25=75\)

\(5^{2x-3}-50=75\)

\(5^{2x-3}=75+50\)

\(5^{2x-3}=125\)

\(5^{2x-3}=5^3\)

\(5^{2x}=5^{3+3}\)

\(5^{2x}=5^6\)

\(x=6\div2\)

\(x=3\)

 

Answer 2

a,52x−3−2.52=52.3a,52x−3−2.52=52.3

52x−3−2.52=25.352x−3−2.52=25.3

52x−3−2.25=7552x−3−2.25=75

52x−3−50=7552x−3−50=75

52x−3=75+5052x−3=75+50

52x−3=12552x−3=125

52x−3=5352x−3=53

52x=53+352x=53+3

52x=5652x=56

Answer 3

5^2x-3-  2 . 5²= 5². 3

5^{2x - 3}-  2 . 5²= 25 . 3 = 75

2 . 5²= 2 . 25 = 50

5^{2x - 3}= 75 - 50 = 25

vì 25 = 5² vậy 5^{2x - 3}=  5²

suy ra 2x - 3 = 2

2x = 2 + 3 = 5

x = 5 : 2 = 2,5