exam Maths Puzzle Numerical Ability

Using synthetic division, determine whether the numbers are zeros of the polynomial.
5, 0; f(x)=2x^4-8x^3-15x^2+30x-25

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exam Other Question

21-[-(3-4)-2]-5
21-[-3+(-4)-2]-5
21-[-7)-2]-5
21-[-7+(-2)-5
21-(-9)-5
21+9-5
30-5
25

Textbook gives this answer as 17

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A can of green beans is a cylinder with a diameter of 3.5 inches and a height of 6 cm. What is the area of the label around the can?