Ngo has a collection of dimes and quarters with a total value of $5.20. The number of dimes is 4 less than the number of quarters. How many of each coin does he have?

9514 1404 393

Step-by-step explanation:

Let Q represent the number of quarters. Then (Q-4) is the number of dimes, and the total amount of money is ...

  25Q +10(Q -4) = 520

  35Q = 560 . . . . . add 40

  Q = 560/35 = 16

Ngo has 16 quarters and 12 dimes.

225x²+4=0

225x²=0-4

225x²=-4

x²=-4/225

x=±√-4/225

the largest number of the four options is 1.8 x 10-2

you have it in scientific notation.

1.80 x 10-6   = 0.00000180

1.80 x 10-4   = 0.000180 (bigger, or "less small", than the former one)

so

1.8 x 10-2       = 0.0180. as you see. the "less small", or the biggest one of them all.

as you have negative exponent, it means you are dividing 1.8 by 100 (i.e. moving the dot towards left, two times).

if you had positive exponent for the scientific notation, power of tenths, you would be multiplying times 100 (moving the dot towards right) as below:

1.8 x (10)2 = 180

so. if you have negative exponent in scientific notation, move the dot toward left. if it is positive, toward right as many times the exponent tells you.