1. f(x) = -x² + 4x + 1
when x = 1, then:
f(1) = - 1² + 4(1) + 1
(1, 4)
when x = 2, then:
f(2) = - 2² + 4(2) + 1
(2, 5)
when x = 3, then:
f(3) = - 3² + 4(3) + 1
(3, 4)
when x = 4, then:
f(4) = - 4² + 4(4) + 1
(4, 1)
when x = 5, then:
f(5) = - 5² + 4(5) + 1
(5, -4)
Graph:
2. f(x) = 2x² - 8x + 3
when x = 1, then:
f(1) = 2(1)² - 8(1) + 3
(1, -3)
when x = 2, then:
f(2) = 2(2)² - 8(2) + 3
(2, -5)
when x = 3, then:
f(3) = 2(3)² - 8(3) + 3
(3, -3)
when x = 4, then:
f(4) = 2(4)² - 8(4) + 3
(4, 3)
when x = 5, then:
f(5) = 2(5)² - 8(5) + 3
(5, 13)
Graph:
3. f(x) = -1/2 x² - 2x + 3
when x = 1, then:
f(1) = -1/2 (1)² - 2(1) + 3
(1, 0.5)
when x = -4, then:
f(-4) = -1/2 (-4)² - 2(-4) + 3
(-4, 3)
when x = 0, then:
f(0) = -1/2 (0)² - 2(0) + 3
(0, 3)
when x = -2, then:
f(-2) = -1/2 (-2)² - 2(-2) + 3
(-2, 5)
when x = -5, then:
f(-5) = -1/2 (-5)² - 2(-5) + 3
(-5, 0.5)
Graph: