Respuestas
Respuesta:
X= -1 <> X= 1/3
Explicación paso a paso:
3X(X) +2X -1 = 0
3X - 1
X 1
(3X-1)(X+1) = 0
.3X -1 = 0
3X=1
X = 1/3
.X + 1= 0
X= -1
Answer:
3
x
2
+
2
x
−
1
=
(
x
+
1
)
(
3
x
−
1
)
Explanation:
The rule to factorise any quadratic is to find two numbers such that
product
=
x
2
coefficient
×
constant coefficient
sum
=
x
coefficient
So for
3
x
2
+
2
x
−
1
we seek two numbers such that
product
=
3
⋅
(
−
1
)
=
−
3
sum
=
2
So we look at the factors of
−
3
. As the product is negative one of the factors must also be negative and the other positive, We compute their sum we get
factor1
factor2
sum
−
3
1
−
2
−
1
3
2
So the factors we seek are
−
1
and
3
Therefore we can factorise the quadratic as follows:
3
x
2
+
2
x
−
1
=
3
x
2
−
x
+
3
x
−
1
∴
3
x
2
+
2
x
−
1
=
x
(
3
x
−
1
)
+
3
x
−
1
∴
3
x
2
+
2
x
−
1
=
(
x
+
1
)
(
3
x
−
1
)
This approach works for all quadratics (assuming it does factorise) , The middle step in the last section can usually be skipped with practice