How do you solve the simultaneous equations $5c + 4d = 23$ and $3c - 5d = -1$ ?

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Answer 1 · 2018-04-18T11:44:19

Solution : $c=3 , d=2$

$5 c+4 d=23 (1) , 3 c -5 d= -1 (2)$ Multiplying equation (1) by

$3$ and equation (2) by $5$ we get,

$15 c+12 d=69 (3) , 15 c -25 d= -5 (4)$ Subtracting equation

(4) from equation (3) we get, $37 d=74 :. d =74/37=2$

Putting $d=2$ in equation (1) we get, $5 c + 4 *2 =23$ or

$5 c= 23 -8 or 5 c = 15 or c = 15/5 =3$

Solution : $c=3 , d=2$ [Ans]

How do you solve the simultaneous equations 5c + 4d = 23 5c + 4d = 23 and 3c - 5d = -13c - 5d = -1?