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Algebraic Expressions and Identities — MATHS STD 8 — Question

Gujarat BoardEnglish MediumSTD 8MATHSAlgebraic Expressions and Identities3 Marks
Question
Find the following products:
$(3x - 4y)(2x - 4y)$
✓

Answer

Here, we will use the identity $(x - a)(x - b) = x^2- (a + b)x + ab.$
$(3x - 4y)(2x - 4y)$
$= (4y - 3x)(4y - 2x)$ (Taking common $- 1$ from both parentheses)
$= (4y)^2- (3x + 2x)(4y) + 3x × 2x$
$= 16y^2- (12xy + 8xy) + 6x^2$
$= 16y^2- 20xy + 6x^2$

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