Answer:
9.6cm
Step-by-step explanation:
x² + bx - 81
there are 2 formula that fit this equation :
>> x² - a² = (x+a)(x-a)
or
>> x² + 2ax² + a² = (x+a)(x+a)
because the last value of our equation is negative value therefore we have to use the first formula >> x² - a² = (x+a)(x-a)
step:
x² + bx - 81
x² + bx - 9²
because we have to follow the first formula x² - a² therefore bx = 0
x² + bx - 9²
bx = 0
b = 0
The polynomial is (mx^3+3)(2x²+5x+2)-(8x^5 +20x^4)
if it is reduced to 8x^3+6x²+15x+6, so we can find the value of m
(mx^3+3)(2x²+5x+2)-(8x^5+20x^4) = <span>8x^3+6x²+15x+6
</span>2mx^5+5mx^4+2mx^3+6x²+15x+6-8x^5-20x^4=<span>8x^3+6x²+15x+6
</span>2mx^5+5mx^4+2mx^3=8x^3+6x²+15x+6-6x²-15x-6+ <span>8x^5+20x^4
</span>= 8x^5+20x^4+<span>8x^3= 4(2x^5+5x^4+2x^3)
finally
</span>m(2x^5+5x^4+2x^3)=<span>4(2x^5+5x^4+2x^3), and after simplification
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C: m=4
<span>4. When the expression is factored x²-3x-18 completely,
</span>
one of its factor is x-6
<span>x²-3x-18=0
</span>D= 9-4(-18)= 81, sqrtD=9 x=3-9/2= -6/2= -3, and x=3+9 / 2= 6
so <span>x²-3x-18= (x-6)(x+6)
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