Jawab:

fungsi kuadrat
titik potong sb x
titik potong sb y
domain
range

1.  titik potong sb x dan  titik  potong sb y
a. f(x) = x² - 3x + 2
titik potong sb x,  y=0
x² - 3x+ 2= 0
(x - 1)(x - 2) =0
x= 1  atau x = 2
titik potong (1,0) dan (2,0)

titik potong sb y, x=0
f(0)= 0²- 3(0) + 2
f(0)= 2
titik potong (0,2)

b.  f(x) = 2x²+ 5x -12
titik potong sb x, y = 0
2x²+5x- 12 = 0
(2x - 3)(x + 4) =0
x =  3/2  atau x = - 4
titik  potong ( -4,0) dan (3/2, 0)


2. domain dan  range
a. f(x)=  x² +8x + 15
domain x ={ x| x ∈ R}
range  f =
xp=  -b/2a = - 8/2  = - 4
yp =  f(-4) = (-4)² +8(-4) + 15
yp = 16 - 32 + 15
yp = - 1
range  y = { y | y≥ - 1 , y ∈ R}

b.  f(x)= 2x² + 5x -  3
domain  x = { x | x ∈ R}
range  f =
xp = - b/2a = - 5/2(2)
xp = - 5/4
yp =  f(-5/4) = 2 (-5/4)² +  5(-5/4) - 3
yp = 2(25/16) -  25/4 - 3
yp =  50/16 - 25/4 - 3
yp = - 49/8
range y = { y | y ≥  -49/8 , y ∈ R}