SOLUTION: Evaluate the polynomial x2- 4y2 - xy for x = 3 and y = -4 Solve by factoring and using the principle of zero products. 2k2 = -30k - 100

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Evaluate the polynomial x2- 4y2 - xy for x = 3 and y = -4 Solve by factoring and using the principle of zero products. 2k2 = -30k - 100      Log On


   

Question 333308: Evaluate the polynomial x2- 4y2 - xy for x = 3 and y = -4
Solve by factoring and using the principle of zero products.
2k2 = -30k - 100
Answer by benazir.sj@gmail.com(109) About Me  (Show Source):
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Evaluate the polynomial x2- 4y2 - xy for x = 3 and y = -4
substitute the values of x and y in the given equation
x^2-4y^2-xy
=(3)^2-4(-4)^2- 3*(-4)
=9 -4*16 +12
=9-64+12
= -43
Solve by factoring and using the principle of zero products.
2k2 = -30k - 100
first lets write the equation in standard form
2k^2+30k+100=0
divide by2 throughout
2k^2/2 +30k/2+100/2=0
k^2+15K+50 =0
k^2+10k +5k+50=0
k(k+10)+5(k+10)=0
(k+10)(k+5)=0
If the product is zero, at least one of the factors is zero.
k+10=0 or k+5=0
k=-10 or k=-5
k=-10,-5