Question

please who can help​

Answer 1

ANSWER:

• Value of the above expression is :

$= \dfrac{ - (a + b)}{b}$

GIVEN:

$= \dfrac{a {}^{2} - b {}^{2} }{b {}^{2} - ab}$

TO FIND:

• Simplify the above expression.

FORMULA USED:

• a²-b² = (a+b)(a-b)

SOLUTION:

$= \dfrac{a {}^{2} - b {}^{2} }{b {}^{2} - ab } \\ \\ = \dfrac{(a + b)(a - b)}{b(b - a)} \\ \\ = \dfrac{ - (a + b)(b - a)}{b(b - a)} \\ cancelling \: (b - a) \: from \: numerator \: and \: denominator \\ \\ = \dfrac{ - (a + b)}{b}$

Value of the above expression is

$= \dfrac{ - (a + b)}{b}$

NOTE:

Some important formulas:

(a+b)² = a²+b²+2ab

(a-b)² = a²+b²-2ab

(a+b)(a-b) = a²-b²

(a+b)³ = a³+b³+3ab(a+b)

(a-b)³ = a³-b³-3ab(a-b)

a³+b³ = (a+b)(a²+b²-ab)

a³-b³ = (a-b)(a²+b²+ab)

(a+b)² = (a-b)²+4ab

(a-b)² = (a+b)²-4ab

Answer 2

-[a+b]/b is the correct answer