Determine whether the system of linear equations has one and only one solution, infinitely many solutions, or no solution. 0.3x − 0.2y = 0.4 −0.2x + 0.5y = 0.1

What is the number 321,000,000 in scientific notation? also what is the number? ?

If f(x) = 4x – 3 and g(x) = 8x + 2, find each function value a.f[g(3)] b.g[f(5)] c.g{f[g(-4)]}

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?