Question

Solve the equation by completing the square. If necessary, round to the nearest hundredth.

x² – 18x = 19
1; 19
–1; 19
3; 6
–3; 1

Answer 1

ax^2+bx=c
REMEMBER THIS

ok
first, make sure that a is 1
done

now take 1/2 of b and square it

-18/2=-9, (-9)^2=81
add that to both sides

x²-18x+81=19+81
x²-18x+81=99
factor perfect square
(x-9)²=100
square root both sides
don't forget positive and negative root
x-9=10
x-9=-10
ad 9 to both sides

x=19
x=-1




answer is -1; 19

2nd choice is answer

Answer 2

Option B. x = -1, 19

Explanation:

The given equation is x² - 18x = 19

We can get the value of x by factorizing the expression or by quadratic formula.

We will try to factorize the equation first. If we find no factors then we will apply quadratic formula to get the value of x.

x² - 18x - 19 = 0

x² - 19x + x - 19 = 0

x(x - 19) + 1(x - 19) = 0

(x - 19)(x + 1) = 0

x = 19, -1 will be the solutions.

So there is no need to apply quadratic formula.

Option B. x = -1, 19 is the answer.