Please help me with this it’s super urgent.

5,600 x 10^3 = a) 560 b) 5,000,600 c) 5,600,000 d) 56,000

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

Aquadratic equation in standard from is written ax^2= bx+c, where a,b and c are real numbers and a is not zero?