Question

factorise 3x squared + 11 x - 20​

Answer 1

Step-by-step explanation:

>Factorise : 10 (3x + 1x ).

Factorise : 10(3x+x1)2+7(2x−x3)−20

Given : 10(3x+x1)2−(3x+x1)−3

Let us consider 3x+x1=a

So we get,

=10a2−a−3

we can further write it as 

=10a2−6a+5a−3

By taking out the common terms

=2a(5a−3)+1(5a−3)

=(2a+1)(5a−3)

Let us replace a by 3x+x1

So we get

=(2(3x+x1)+1)(5(3x+x1

Answer 2

$\huge\color{pink}{\mid{\fbox{\tt{QUESTION}}\mid}}$

• factorise 3x² + 11 x - 20

$\huge\sf\underline\pink{Solution:-}$

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⟼ first multiply 3×20

=60

NOW,

-15+4= -11

and

-15×4 = -60

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$3x {}^{2} - 11x - 20 \\ \\ = 3x {}^{2} + 15x - 4x - 20 \\ \\ = 3x(x + 5) - 4(x + 5) \\ \\ = (x + 5)(3x - 4)$

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