Ihave a math test tomorrow and i need to know how to simplify s+t+s wondering if someone could

What number should be added to the expression x^2+3x+ in order to create a perfect square trinomial? 3/2 3 9/4 9

Which of the following pair(s) of circles have las a common external tangent? select all that apply. a and b a and c b and c

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.