What is the best estimate for the product of 289 and 7 ?

The sum of two numbers is 58. the first number is 8 less than half the second number. let  c  represent the first number. let  drepresent the second number. which statements about solving for the two numbers are true? check all that apply. the equation    represents the sum of the two numbers. the equation    represents the sentence “the first number is 8 less than half the second number.”the equation    represents the relationship between the two numbers. the equation    represents the sum of the two numbers. the number  d  is 14.the number  c  is 44.the number  c  is 14.the number  d  is 44.

What is the missing step in this proof ?

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?