Find the solutions of x^2 + x - 12 = 0
Answers
Answered by
1
Step-by-step explanation:
x^2+ x-12=0
x^2+4x-3x-12=0
x(x+4)-3(x+4)=0
(x+4)(x-3)=0
x=3, -4
Answered by
0
Step-by-step explanation:
We can Split the Middle Term of this expression to factorise it and thereby find solutions.
In this technique, if we have to factorise an expression like
ax2+bx+c
, we need to think of 2 numbers such that:
N1⋅N2=a⋅c=1⋅−12=−12 AND
N1+N2=b=−1
After trying out a few numbers we get
N
1
=
3
and
N
2
=
−
4
3
⋅
−
4
=
−
12
, and
3
+
(
−
4
)
=
−
1
x
2
−
x
−
12
=
x
2
−
4
x
+
3
x
−
12
x
(
x
−
4
)
+
3
(
x
−
4
)
=
0
(
x
+
3
)
(
x
−
4
)
=
0
Now we equate the factors to zero.
x
+
3
=
0
,
x
=
−
3
x
−
4
=
0
,
x
=
4
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