Answer:
12
Step-by-step explanation:
18 - 27 - 90 = 63 degrees. Special thingy so answer is above
Let x is Casey's sister age.
<span>3 years ago:
</span><span>Casey was twice as old as his sister: 2a - 3
Now:
</span><span>he is 5 years older than his sister: a + 5
2a - 3 = a + 5
subtract a to both sides
2a - 3 -a = a + 5 - a
simplify
a - 3 = 5
add 3 to both sides
a - 3 + 3 = 5 + 3
simplify
a = 8
His sister age is 8 years old now.
</span>Now:
he is 5 years older than his sister: a + 5 = 8 + 5 = 13
<span>
proof:
so 3 years ago,
his sister age: 8 - 3 = 5
Casey age 3 years ago:
13 - 3 = 10 (</span>C<span>asey was twice as old as his sister 3 years ago</span>)
<span>
Answer:
Casey is 13 years old now.
</span>
Sometimes writing can be an issue. Finding inspiration can be difficult... Might I suggest... A mystery perhaps. Or a fantasy.
The best way is to recognise that, if
x
=
5
is a root, then
x
−
5
=
0
, and ditto for the other two roots. So we have
x
−
5
,
x
−
i
,
x
+
i
all equalling zero. To find our polynomial, we just multiply the three terms together:
(
x
−
5
)
(
x
−
i
)
(
x
+
i
)
=
(
x
2
−
i
x
−
5
x
+
5
i
)
(
x
+
i
)
=
x
3
+
i
x
2
−
i
x
2
−
(
i
2
)
x
−
5
x
2
−
5
i
x
+
5
i
x
+
5
i
2
which simplifies to
x
3
−
5
x
2
+
x
−
5
.
