9x - 2y = -21 /·3 2x + 3y = 16 /·2
27x - 6y = -63 4x + 6y = 32
31x = -31 /:31 x = -1
2x + 3y = 16 ⇒ 3y = 16 - 2x 3y = 16 - 2 · (-1) 3y = 18 /:3 y = 6 Ans.: x = -1 y = 6
{ 9 x − 2 y = − 21/ ∗ 3 2 x + 3 y = 16/ ∗ 2 { 27 x − 6 y = − 63 4 x + 6 y = 32 − − − − − − − − − 31 x = − 31/ : 31 x = − 1
9 ∗ ( − 1 ) − 2 y = − 21 − 2 y = − 21 + 9 − 2 y = − 12/ : ( − 2 ) y = 6 { x = − 1 y = 6
To solve the equations 9 x − 2 y = − 21 and 2 x + 3 y = 16 using elimination, first manipulate the equations to eliminate one variable. Finally, substitute to find the values of x and y , which results in x = − 1 and y = 6 .
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