74 a i It means that the constant terms in B1 2 B1 for first condition H both expressions are positive, or if one B1 B1 for second condition is positive and one is negative, their sum is positive. ii It means that the constant terms in B1 B1 for first condition both expressions are negative, or if one B1 B1 for second condition is positive and one is negative their sum is negative. iii The expression is the difference of two B1 B1 for clear explanation squares. b i B1 B1 for correct example explained For example, (4x + 2)(x 1) – = 4x2 2x 2 as required. – – ii B1 B1 for correct example explained For example, (3x + 1)(x + 1) = 3x2 + 4x + 1 as required. B1 B1 for complete clear explanation c If it is positive then both expressions have the same sign. If it is negative then the expressions 8 have different signs.
74 a i ii iii b i ii c It means that the constant terms in both expressions are positive, or if one is positive and one is negative, their sum is positive. It means that the constant terms in both expressions are negative, or if one is positive and one is negative their sum is negative. The expression is the difference of two squares. For example, (4x + 2)(x – 1) = 4x2 – 2x – 2 as required. For example, (3x + 1)(x + 1) = 3x2 + 4x + 1 as required. If it is positive then both expressions have the same sign. If it is negative then the expressions have different signs. B1 B1 B1 B1 B1 B1 B1 B1 2 B1 for first condition B1 for second condition B1 for first condition B1 for second condition B1 for clear explanation B1 for correct example explained B1 for correct example explained B1 for complete clear explanation H 8
Higher_Skills_Algebra_MarkScheme_AQA.docx