Answers − Substitution into Formulae − 2

  1.   What is the value of 7 + 2a² when a = 6?

	7 + 2a2	= 7 + 2(62)
		= 7 + (2 × 36)
		= 7 + 72
		= 79

  2.   What is the value of 2x² + 3 when x = 60?

	2x2 + 3	= 2(602) + 3
		= (2 × 3600) + 3
		= 7200 + 3
		= 7203

  3.   What is the value of 35 + 4y² when y = −5?

	35 + 4y2	= 35 + 4(−52)
		= 35 + (4 × 25)
		= 35 + 100
		= 135

  4.   What is the value of 10 + 3a² + b when a = 4 and b = −7?

  5.   What is the value of 4 + x²y + z when x= −3, y = −7 and z = 6?

  6.   What is the value of 2a² + 10ab − 3b² when a = 7 and b = −3?

  7.   What is the value of 3a + 4a² + 6b − b² when a = 5 and b = 9?

  8.   What is the value of 9a + 2a² + 20ab + 7b − b² when a = 3 and b = 4?

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