Answer:
2.44
Step-by-step explanation:
Given: x³ + 2x² - 5ax - 7 and x³ + ax² - 12x + 6
Also, R1 + R2 = 6
in order to find the value of a:
Let p(x) = x³ + 2x² - 5ax - 7 and q(x) = x³ + ax² - 12x + 6
Using remainder theorem i.e if a polynomial p(x) is divisible by polynomial of form x - a then remainder is given by p(a).
Then,
R1 = p( -1 ) = (-1)³ + 2(-1)² - 5a(-1) - 7 = -1 + 2 + 5a - 7 = 5a - 6
R2 = q( 2 ) = 2³ + a(2)² - 12(2) + 6 = 8 + 4a - 24 + 6 = 4a - 10
Now,
R1 + R2 = 6
5a - 6 + 4a - 10 = 6
9a = 22
a=2.44
Therefore, Value of a is 2.44
X = pencils, y = pens
8x + 6y = 8.50
4x + 4y = 5.....multiply by -2
----------------
8x + 6y = 8.50
-8x - 8y = -10 (result of multiplying by -2)
-----------------add
-2y = - 1.50
y = -1.50 / -2
y = 0.75 <=== pens cost 0.75
4x + 4y = 5
4x + 4(0.75) = 5
4x + 3 = 5
4x = 5 - 3
4x = 2
x = 2/4
x = 0.50 <== pencils cost 0.50
The answer is 31.832142857.
(-5/6)+(-5/6) have the same denominator (number at bottom of fraction), so all you have to do is add the numerator(top number). So -5 +-5 =-10 . Now you have -10/6, which simplifies to -5/3.
Hope this helps :)
The answer would be <em>29.5562243957</em>.
