Questions on Algebra: Matrices, determinant, Cramer rule answered by real tutors!

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Question 162554: 9. (4, -10), (1, -1)
x y 1 x y
4 -10 1 4 -10
1 -1 1 1 -1
(x)(-10)(1)+(y)(1)(1)+(1)(4)(-1)+(1)(-10)(1)-(-1)(1)(x)-(1)(4)(y)=
-10x+y+(-4)-(-10)-(-x)-4y=
-9x-3y+6=0
-9x-3y=-6
-3y+(-9x)=-6
-3y=-6+9x
-y=2+3x
Y=-3x-2
Can you find my sign error? Im sure im just overlooking something,but I can't find it. Thank you so much!: 9. (4, -10), (1, -1)
x y 1 x y
4 -10 1 4 -10
1 -1 1 1 -1
(x)(-10)(1)+(y)(1)(1)+(1)(4)(-1)+(1)(-10)(1)-(-1)(1)(x)-(1)(4)(y)=
-10x+y+(-4)-(-10)-(-x)-4y=
-9x-3y+6=0
-9x-3y=-6
-3y+(-9x)=-6
-3y=-6+9x
-y=2+3x
Y=-3x-2
Can you find my sign error? Im sure im just overlooking something,but I can't find it. Thank you so much!
Answer by checkley77(3848) About Me  (Show Source):
You can put this solution on YOUR website!
(x)(-10)(1)+(y)(1)(1)+(1)(4)(-1)+(1)(-10)(1)-(-1)(1)(x)-(1)(4)(y)=
IF this step is correct then:
-10x+y-4[-10]+1x-4y
*******(+10)***** is your mistake.