SOLUTION: Find the value of x+y in the following [3x-2] [x y] = [42 4] ..........[3 4] *I added the dots so the 3 and 4 could go under the x and y as one matrix

Question 190068: Find the value of x+y in the following
[3x-2] [x y] = [42 4]
..........[3 4]

*I added the dots so the 3 and 4 could go under the x and y as one matrix
Answer by cutepiscean5(19) (Show Source): You can put this solution on YOUR website!
Find the value of x+y in the following
[3x-2] [x y] = [42 4]
..........[3 4]
Solution:
_________
we have a 1x2 matrix multiplied with a 2x2 matrix, which results in a 1x2 matrix again.
So, we first take the Left and side of this equation and multiply both the matrices and get the answers in terms of x and y.
we have:
[3x -2] [x y]
...............[3 4]
=> AMP Parsing Error of [ [ ( (3x)(x) + (-2)(3) ) .......... ( (3x)(y) + (-2)(4) ) ] ]: Invalid expression '[((3\x)(x)+(-2)(3))..........((3\x)(y)+(-2)(4))]': syntax error at /home/ichudov/project_locations/algebra.com/templates/Algebra/Expression.pm line 203. .

we have got two terms which have been determined by multiplication, we now simplify them...
first element of the row is
and, second element of the row is
now we compare both sides of the original equation and we get:
..........(1)
and
............(2)
we have two equations and two variables x & y, we solve for them.
from equation (1) we have:

=>
=>
=>
=>
=> or
From equation (2),
when we plug in x = 4 , we get:

=>
=>
=>
=>
=>
when we plug in x = -4 , we get:

=>
=>
=>
=>
=>
Thus x+y = 4+1 = or x+y = -4-1 =
Hope this helps.

RELATED QUESTIONS
find the value of y and x in the equation... (answered by Edwin McCravy)

I'm still having trouble with the graph method.Could someone please show me how to do a... (answered by jim_thompson5910)

Id have a question if x varies inversely as y and x=2 when y=8, and i should find x when... (answered by solver91311)

if x=-3 and y=4 find the value of x... (answered by ewatrrr)

I need help solving the following for y in terms of x: x = y^4 + y^2 + 1 I... (answered by jim_thompson5910)

Find the value of X and Y in each of the following... (answered by Alan3354)

if x-y=-6 and xy=4, then find the value of... (answered by ankor@dixie-net.com)

Which of the following equations could represent the relationship between x and y in the... (answered by ikleyn)

for which of the following are x and y inversely proportional? 1. y=4x 2. y=x/4 3.... (answered by MathLover1)