Find missing number from letter n ! Please

1. n= 20 /13

2. n=10

3. n=35

4. n=9

That's all I could do, I got tired of typing lol

Step-by-step explanation:

1.  4/n=13/5 we cross multiply, (4)*(5)=13*n, 20=13n Flip the equation.  13n=20, divide 13 on both sides, 13n/13=20/13, n= 20 /13

2. 9/6= 15/n, we cross multiply 9*n=(15)*(6), 9n=90, Divide both sides by 9. 9n/9=90/9 n=10

3. 28/4=n/5 Cross-multiply, (28)*(5)=n*(4), 140=4n Flip the equation.4n=140 Divide both sides by 4. 4n/4=140/4 n=35

4. n/6=6/4 we cross multiply,n*(4)=(6)*(6), 4n=36, Divide both sides by 4 4n/4=36/4.  n=9

25.2

step-by-step explanation:

2+4x6-8/10= 25.2

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225