Solve by addition or substitution.-4x + 2y = 34x - 2y = 3
A. 
B. 
C. {(r, s)|-4r + 2s = 3}
D. ?
Answer: D
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Find the logarithm. Give an approximation to four decimal places.ln 225
A. 2.3522 B. 5.4161 C. 83.0258 D. 0.1841
Evaluate the expression using the values given in the table.(g?f)(1)
A. -5 B. 11 C. 7 D. -1
Solve the problem.The focal length f of a lens with index of refraction n is 
= (n - 1)
where R1and R2 are the radii of curvature of the front and back surfaces of the lens. Express f as a rational expression.
A. f = 
B. f = 
C. f = 
D. f = 
Solve the problem.A doctor has told a sick patient to take vitamin pills. The patient needs at least 40 units of vitamin A, at least 9 units of vitamin B, and at least 30 units of vitamin C. The red vitamin pills cost 
each and contain 7 units of A, 1 unit of B, and 2 units of C. The blue vitamin pills cost 
each and contain 3 units of A, 1 unit of B, and 6 units of C. How many pills should the patient take each day to minimize costs?
A. 9 red and 0 blue B. 6 red and 3 blue C. 3 red and 6 blue D. 7 red and 2 blue