Classify each number according to its value. 4.2 × 10-6
2.1 × 10-3
3.1 × 10-2
3.2 × 10-5
3.5 × 10-4
5.8 × 10-3
5.2 × 10-4

Solve for x -2.3(r - 1.2 ) = -9.66 enter you answer as decimal.

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

Celeste wants to have her hair cut and permed and also go to lunch. she knows she will need $50. the perm cost twice as much as her haircut and she needs $5 for lunch. how much does the perm cost?