Question

m-n=0.9 and mn=0.36 find m+n and m 2 - n2

Answer 1

(m-n)² = m²+n²-2mn
(0.9)² = m²+n²-2(0.36)
0.81+0.72 = m²+n²
1.53 = m²+n²

(m+n)² = m²+n²+2mn
(m+n)² = 1.53+2(0.36)
(m+n)² = 1.53+0.72
(m+n)² = 2.25
(m+n) = √2.25 = 1.5


m²-n² = (m+n)(m-n)
m²-n² = 1.5(0.9) =>1.35
hope this helps

Answer 2

Answer:

1) m+n = ±1.5

2) m²-n² = ±1.35

Step-by-step explanation:

1) We know that (a+b)² - (a-b)² = 4ab

∴ (a+b)² = (a-b)² + 4ab

⇒ (m+n)² = (0.9)² + 4(0.36)

⇒ (m+n)² = 0.81 + 1.44

⇒ (m+n)² = 2.25

⇒ m+n = √2.25

⇒ m+n = ±1.5

2) We know that (a+b)(a-b) = a²-b²

∴  (m+n)(m-n) = m²-n²

⇒ (±1.5)(0.9) = m²-n²

⇒ m²-n² = (±1.5)(0.9)

⇒ m²-n² = ±1.35