Respuesta :
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
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:
Option B. x = -1, 19
Step-by-step 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.