1. Find the sum of (2p3 – 8)and(p? + 9p + 18)
2. Subtract (7.x2 - 4x + 2)from(8x2 - x + 6 )
Answers
Answer:
Answer
Explanation
1. answer ....Based on the given conditions, write:
Remove the parentheses:
Combine like terms:
Rewrite the expression:
2. answer
Answer: ....Simplify (x3 + 3x2 + 5x – 4) – (3x3 – 8x2 – 5x + 6)
The first thing I have to do is take that "minus" sign through the parentheses containing the second polynomial. Some students find it helpful to put a "1" in front of the parentheses, to help them keep track of the minus sign.
Here's what the subtraction looks like, when working horizontally:
(x3 + 3x2 + 5x – 4) – (3x3 – 8x2 – 5x + 6)
(x3 + 3x2 + 5x – 4) – 1(3x3 – 8x2 – 5x + 6)
(x3 + 3x2 + 5x – 4) – 1(3x3) – 1 (–8x2) – 1(–5x) – 1(6)
x3 + 3x2 + 5x – 4 – 3x3 + 8x2 + 5x – 6
x3 – 3x3 + 3x2 + 8x2 + 5x + 5x – 4 – 6
–2x3 + 11x2 + 10x –10
And here's what the subtraction looks like, when going vertically:
\small{ \begin{array}{rrrr}x^3&+3x^2&+5x&-4\\-(3x^3&-8x^2&-5x&+6)\\ \hline\end{array} }
x
3
−(3x
3
+3x
2
−8x
2
+5x
−5x
−4
+6)