Question

The equation x2 – 1x – 90 = 0 has solutions {a, b}. What is a + b?

Answer 1

(x-10)(x+9) =0
×=10 x=-9
10 + (-9)
= 1

Answer 2

Answer:

The value of a+b is 1.

Step-by-step explanation:

The given equation is

$x^2-1x-90=0$

It is given that this equation has two solutions {a,b}.

First of all find the factors of given equation. The middle term can be written as -10x+9x.

$x^2-10x+9x-90=0$

$(x^2-10x)+(9x-90)=0$

Taking out common from each parenthesis.

$x(x-10)+9(x-10)=0$

$(x-10)(x+9)=0$

Using zero product property, we get

$x-10=0\Rightarrow x=10$

$x+9=0\Rightarrow x=-9$

The value of a is 10 and b is -9. The sum of both the solutions is

$a+b=10-9=1$

Therefore the value of a+b is 1.