book Maths Puzzle Numerical Ability

Can someone tell me how to solve the following problem:
7(2+3x)+8

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book Other Question

If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? find the exact value of cos 105 degrees WITHOUT USING TABLES OR A CALCULATOR. be sure to show your work.