Question

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

Answer 1

Answer:

a+b=1

Step-by-step explanation:

we know that

The formula to solve a quadratic equation of the form $ax^{2} +bx+c=0$ is equal to

$x=\frac{-b(+/-)\sqrt{b^{2}-4ac}} {2a}$

in this problem we have

$x^{2} -x-90=0$  

so

$a=1\\b=-1\\c=-90$

substitute in the formula

$x=\frac{1(+/-)\sqrt{-1^{2}-4(1)(-90)}} {2(1)}$

$x=\frac{1(+/-)\sqrt{361}} {2}$

$x=\frac{1(+/-)19} {2}$

$x=\frac{1(+)19} {2}=10$

$x=\frac{1(-)19} {2}=-9$

so

a=10, b=-9

a+b=10-9=1

Answer 2

Good evening ,

______

Answer:

a+b=1

___________________

Step-by-step explanation:

For such equation which has the form : mx² + nx + p = 0

There is a rule in this course that tells as: a + b = -(n)/m

We have m=1 and n= (-1) then a+b= -(-1)/1 = 1/1 = 1.

:)