Question

Complete it .....
The QuaDratic

Answer 1

Comparing with b^2 - 4ac,

( 2a ) ^2 - 4 × a × 4

0 = 4a^2 - 16a

0 = 4a ( a - 4 )

a = 4

We assumed R - 4 = a

So, R - 4 = 4

R = 4 + 4 = 8.

Answer 2

Answer:

k = 4,8

Step-by-step explanation:

Given Equation is (k - 4)x² + 2(k - 4)x + 4 = 0

On comparing with ax² + bx + c = 0

a = k - 4, b = 2(k - 4), c = 4.

∴ D = 0

b² - 4ac = 0

⇒ [2(k - 4)]² - 4(k - 4)(4) = 0

⇒ (2k - 8)² - 4(k - 4) * (4) = 0

⇒ 4k² + 64 - 32k - 16(k - 4) = 0

⇒ 4k² + 64 - 32k - 16k + 64 = 0

⇒ 4k² - 48k + 128 = 0

⇒ k² - 12k + 32 = 0

⇒ k² - 8k - 4k + 32 = 0

⇒ k(k - 8) - 4(k - 8) = 0

⇒ (k - 4)(k - 8) = 0

⇒ k = 4,8

Hope it helps!