Answer:
x = 2±sqrt(11)
Step-by-step explanation:
x^2 -4x - 7 =0
Add 7 to each side
x^2 -4x -7+7 =0+7
x^2 -4x =7
To complete the square take the coefficient of the x term and divide by 2 and then square it. Add it to both sides
-4 /2 = -2 then square
(-2)^2 = 4
Add 4 to both sides
x^2 -4x+4 =7+4
x^2 -4x+4 = 11
Factor the left side into (x-b/2)^2
(x-2)^2 =11
Take the square root of each side
sqrt((x-2)^2) =±sqrt(11)
x-2 = ±sqrt(11)
Add to to each side
x-2+2 = 2±sqrt(11)
x = 2±sqrt(11)
Answer:
12√5
Step-by-step explanation:
According to the attached sketch, there are 2 triangles which we need to focus on, triangle A (in yellow) and triangle B (In red).
If you look at triangle A, we notice that X is the hypotenuse of triangle A. This means that X must be the largest length in triangle A, hence we can say that x must be greater than 24 (or 24 < x)
Now look at triangle B, in this case, they hypotenuse is 30 and x is the length of one of the sides. This means that x must be shorter than the hypotenuse (i.e x < 30)
from the 2 paragraphs above, we can see now that we can assemble an inequality in x
24 < x < 30
If we look at the choices, we can immediately ignore 33 because x must be less than 30,
working out the choices, we find that the only choice which falls into the range 24<x<30 is the 2nd choice 12√5 (= 26.83) (which is the answer)
The last 2 choices give values smaller than 24 and are hence cannot be the answer
I think it’s the third one and the last two. I’m sorry if it’s wrong
66,190 is the Answer if you add 80 to 110 and then add 190 to 66000