Question

factorise :- 2a2+a-45.​

Answer 1

Answer:

2a2+a-45

2a2+10a-9a-45

2a(a+5)-9(a+5)

(a+5)(2a-9)

a=-5 , 9/2

thanks.............

Answer 2

Answer:

(2a−9)(a+5)

Step-by-step explanation:

2a²+a-45

Factor the expression by grouping. First, the expression needs to be rewritten as 2a²+pa+qa−45. To find p and q, set up a system to be solved.

p+q=1

pq=2(−45)=−90

Since pq is negative, p and q have the opposite signs. Since p+q is positive, the positive number has greater absolute value than the negative. List all such integer pairs that give product −90.

−1,90

−2,45

−3,30

−5,18

−6,15

−9,10

Calculate the sum for each pair.

−1+90=89

−2+45=43

−3+30=27

−5+18=13

−6+15=9

−9+10=1

The solution is the pair that gives sum 1.

p=−9

q=10

Rewrite 2a² +a−45 as (2a² −9a)+(10a−45).

( 2a² −9a)+(10a−45)

Factor out a in the first and 5 in the second group.

a(2a−9)+5(2a−9)

Factor out common term 2a−9 by using distributive property.

(2a−9)(a+5)

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