What number has the same value as 30 tens

30 tens has the same value as 300.

30 × 10 = 300

Look at each place. The value for that place is everything to the left...

Hundreds place -
3 hundreds = 300

Tens place = 30 tens = 300

Ones place = 300 ones = 300

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"