If X + Y = 1 and Xy = -12; Find: X - Y

If x + y = 1 and xy = -12; find:
x - y

Sum

(x + y)² = (1)²
⇒ x² + y² + 2xy
= 1
⇒ x² + y²
= 1 - 2(-12)
= 1 + 24
= 25
Now, (x - y)²
= x² + y² - 2xy
= 25 - 2(-12)
= 25 + 24
= 49
⇒ x - y
= ±7.

shaalaa.com

Is there an error in this question or solution?

Chapter 3: Expansions - Exercise 4.1

Chapter 3 Expansions
Exercise 4.1 | Q 14.1

Write the following cube in expanded form:

`[x-2/3y]^3`

Evaluate the following using identities:

(1.5x²− 0.3y²) (1.5x²+ 0.3y²)

Simplify the following

`(7.83 + 7.83 - 1.17 xx 1.17)/6.66`

Write in the expanded form: `(x + 2y + 4z)^2`

Find the value of 64x³ − 125z³, if 4x − 5z = 16 and xz = 12.

Simplify of the following:

(x+3)³ + (x−3)³

Find the following product:

(3x − 4y + 5z) (9x² +16y²+ 25z² + 12xy −15zx + 20yz)

If a + b + c = 9 and ab + bc + ca =23, then a³+ b³+ c³ − 3abc =

If a - b = 4 and a + b = 6; find
(i) a² + b²(ii) ab

If p + q = 8 and p - q = 4, find:
p²+ q²