2ax²+x+3-y=0 Y=ax²-2x+a Tentukan nilai 4a²+2a-1

Jawab:

substitusi

y = y

2ax² + x + 3 = ax² – 2x + a

2ax² – ax² + x + 2x + 3 – a = 0

ax² + 3x + 3 – a = 0

maka

a = a

b = 3

c = 3 – a

mempunyai satu penyelesaian maka

D = 0

b² – 4ac = 0

(3)² – 4(a)(3 – a) = 0

9 – 4a (3 – a) = 0

9 – 12a + 4a² = 0

(3 – 2a) (3 – 2a) = 0

(3 – 2a)² = 0

3 – 2a = 0

2a = 3

a = 3/2

akan didapat a = 3/2

maka nilai dari 4a² + 2a – 1

= 4(3/2)² + 2(3/2) – 1

= 4(9/4) + 3 – 1

= 9 + 3 – 1

= 11