Step-by-step explanation:
x²-4x+3=0
x²-4x=-3
take half of -4 square it and add it to both side
x²-4x+(-2)²=4-3
(x-2)²=1
x-2=±1
x=2±1
x=1,3
Answer:
x
=
2
±
√
7
Explanation:
there are no whole numbers which multiply to - 3
and sum to - 4
we can solve using the method of
completing the square
the coefficient of the
term is 1
∙
add subtract
(
1
coefficient of the x-term
) 2 to x2 − 4 x ⇒ x 2 +2(− 2 ) x + 4 − 4 − 3 = 0 ⇒ ( x − 2 )2 − 7 =0 ⇒ ( x − 2 ) 2 = 7
take the square root of both sides
⇒ x − 2 = ± √ 7 ←
note plus or minus
⇒ x = 2 ± √ 7←
exact solutions
B. x² - 13x + 42
The completed reaction is
CaCO3 + 2 HCl → (Ca+2 + 2 Cl-)aq + H2O + CO2↑
5000
The 5 is in the "thousand" place, so it would be 5000