I need to know £400 in euros and how to convert it

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

Which expressions are equivalent to k/2 choose 2 answers: a k-2 b 2/k c 1/2k d k/2 e k+k

One number is 4 less than 3 times a second number. if 3 more than two times the first number is decreased by 2 times the second number, the result is 11. use the substitution method. what is the first number?