Question

Wenn man weiß dass 2a + 3b=5 und 2c+b=7 berechne 4a+7b+2c


Ofer 15 puncte

Answer 1

2a+3b=5⇔4a+6b     = 10         (1)

2c+b=7⇔          b+2c =7    (+)        (2)

((1) + (2))     ⇒4a+7b+2c=17

Answer 2

2 a + 3 b = 5    si    2 c + b = 7

4 a + 7 b + 2 c = 17

4 a + (  6 b + b ) + 2 c =

= ( 4 a + 6 b ) + ( 2 c + b ) =

= 2 × ( 2 a + 3 b ) + 7 =

= 2 × 5 + 7 =

= 10 + 7 =

= 17