Question

adding and subtracting polynomials
simplify the following expressions.
give your answers as simplified expressions written in descending order.
original expresion | simplified expression
$(2x + 9) + (-9x + 4)$ |
$(3x + 8) - (2x + 9)$ |
$-4(-9x + 4) + x$ |
$-x(-9x + 4) + (-6x^2 - 5x + 1)$ |
question help: video 1 video 2 video 3 read 1 read 2
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Explanation:

Step1: Combine like terms (1st expr)

$(2x - 9x) + (9 + 4) = -7x + 13$

Step2: Distribute & combine like terms (2nd expr)

$3x + 8 - 2x - 9 = (3x - 2x) + (8 - 9) = x - 1$

Step3: Distribute & combine like terms (3rd expr)

$(-4)(-9x) + (-4)(4) + x = 36x - 16 + x = 37x - 16$

Step4: Distribute & combine like terms (4th expr)

$9x^2 - 4x - 6x^2 - 5x + 1 = (9x^2 - 6x^2) + (-4x - 5x) + 1 = 3x^2 - 9x + 1$

Answer:

1. $\boldsymbol{-7x + 13}$
2. $\boldsymbol{x - 1}$
3. $\boldsymbol{37x - 16}$
4. $\boldsymbol{3x^2 - 9x + 1}$