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2 votes
A = x² + xy +2y-1
A+B= 2x² - xy - 4y-1
a) find A-B
b) if (A-B) = X
find y​

1 Answer

3 votes

Answer:

see explanation

Explanation:

Given the 2 equations

A = x² + xy + 2y - 1 → (1)

A + B = 2x² - xy - 4y - 1 → (2)

From (2)

B = 2x² - xy - 4y - 1 - A

= 2x² - xy - 4y - 1 - (x² + xy + 2y - 1) ← distribute parenthesis

= 2x² - xy - 4y - 1 - x² - xy - 2y + 1 ← collect like terms

= x² - 2xy - 6y

Hence

A - B = x² + xy + 2y - 1 - (x² - 2xy - 6y) ← distribute parenthesis

= x² + xy + 2y - 1 - x² + 2xy + 6y ← collect like terms

= 3xy + 8y - 1

(b)

Given A - B = x, then

x = 3xy + 8y - 1 ( add 1 to both sides )

x + 1 = 3xy + 8y ← factor out y from each term

x + 1 = y(3x + 8) ← divide both sides by (3x + 8)

y =
(x+1)/(3x+8)

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