SOLUTION: Solve the system of equations. {{{3j^2 + 17j + 8k - 84 = 0}}} {{{-j + 8k - 63 = 0}}} j:___, k:___ and j:___, k:___

Algebra.Com
Question 876476: Solve the system of equations.


j:___, k:___
and
j:___, k:___

Answer by ankor@dixie-net.com(22740)   (Show Source): You can put this solution on YOUR website!


Subtract the 2nd equation from the first equation


---------------------------------subtraction eliminates k
3j^2 + 18j + 0 - 21 = 0
A quadratic we can factor
(3j - 3)(j + 7) = 0
3j = 3
j = 1
and
j = -7
:
Use the 2nd equation to find k
when j = 1
-1 + 8k - 63 = 0
8k = 63 + 1
k = 8, when j = 1
:
When j= -7
7 + 8k - 63 = 0
8k = 63 - 7
k = 56/8
k = 7 when j = -7
:
:
Check solutions in 1st equation
j=1, k=8
3(1^2) + 17(1) + 8(8) - 84 = 0
3 + 17 + 64 - 84 = 0
j=-7, k=7
3(-7^2) + 17(-7) + 8(7) - 84 = 0
147 - 119 + 56 - 84 = 0

RELATED QUESTIONS

If 4j-k=11 and k=3j then... (answered by ReadingBoosters)
an: if A =4+7j 2k and 2j+6j-8k where I J K are multiple perpendicular vector calculate... (answered by Edwin McCravy)
Find modulus of complex number z= (((3-4j)(3j-2))/-j) i have tried... (answered by rothauserc,greenestamps)
2(j+k)=m;k (answered by MathLover1)
solve the following equation:... (answered by tommyt3rd)
Given that a= 2i+3j-k, b=i-j+2k and c= 3i+4j+k, find a +2b - c? Find the area of... (answered by robertb)
After j candies were given to k kids, each kid has the same number of candies, with four... (answered by richard1234)
-k-(-8k) (answered by MathLover1)
show that the vectors a=2i+3j-k and b=3i-j+3k are... (answered by Alan3354)