Question

Factorise 8a2 + 18a – 5 by spitting the middle term.​

Answer 1

Answer:

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Step-by-step explanation:

8a^2-2a+20a-5

2a(4a-1)+5(4a-1)

(2a+5)(4a-1)

Answer 2

Trying to factor by splitting the middle term

Factoring 8a2-18a-5

The first term is, 8a2 its coefficient is 8 .

The middle term is, -18a its coefficient is -18 .

The last term, "the constant", is -5

• Step-1 : Multiply the coefficient of the first term by the constant 8 × -5 = -40

• Step-2 : Find two factors of -40 whose sum equals the coefficient of the middle term, which is -18 .

-40 + 1 = -39

-20 + 2 = -18 That's it

• Step-3 : Rewrite the polynomial splitting the middle term using the two factors found in step 2 above, -20 and 2

8a2 - 20a + 2a - 5

• Step-4 : Add up the first 2 terms, pulling out like factors :

4a × (2a-5)

Add up the last 2 terms, pulling out common factors :

1 × (2a-5)

• Step-5 : Add up the four terms of step 4 :

(4a+1)(2a-5)

Which is the desired factorisation

$bts \: exo$