How do you solve $-2.5x + 1.4y = -10.2$ and $1.2x - 4.5y = -21.9$ ?

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Answer 1 · 2018-04-25T11:58:23

Solution: $x=8,y=7$

$-2.5 x +1.4 y = -10.2 (1) ; 1.2 x -4.5 y = -21.9 (2)$

Multiplying by $10$ on both sides of the equations (1) and (2) we

get, $-25 x +14 y = -102 (3) ; 12 x -45 y = -219 (4)$

Multiplying by $12$ on both sides of the equation (3) we get,

$-300 x +168 y = -1224 (5 )$

Multiplying by $25$ on both sides of the equation (4) we get,

$300 x - 1125 y = -5475 (6)$ Adding equations (5) and (6)

we get, $-957 y = -6699 :. y =( -6699)/-957= 7$ Putting

$y=7$ in equation (3) we get $-25 x + 14*7 =-102$ or

$-25 x =-102-98 or -25 x= -200 or x = (-200)/-25=8$

Solution: $x=8,y=7$ [Ans]

How do you solve -2.5x + 1.4y = -10.2-2.5x + 1.4y = -10.2 and 1.2x - 4.5y = -21.91.2x - 4.5y = -21.9?