Question

2+2ori paranteză pătrată2+3ori(2+404:a)-612:6închid paranteza pătrată egal 420.

Answer 1

Răspuns:  x = 4

Explicație pas cu pas:

2 + 2 × [2 + 3× ( 2 + 404 : a ) - 612 : 6 ] = 420

2 × [2 + 3× ( 2 + 404 : a ) - 102] = 420 - 2

2 × [2 + 3× ( 2 + 404 : a ) - 102 ] = 418

2 + 3× ( 2 + 404 : a ) - 102 = 418 : 2

2 + 3× ( 2 + 404 : a ) - 102 = 209

2 + 3× ( 2 + 404 : a ) = 209 + 102

2 + 3× ( 2 + 404 : a ) = 311

3× ( 2 + 404 : a ) = 311 - 2

3× ( 2 + 404 : a ) = 309

2 + 404 : a = 309 : 3

2 + 404 : a = 103

404 : a = 103 - 2

404 : a = 101

a = 404 : 101

a = 4 → numărul aflat prin metoda mersului invers

Answer 2

$2+2\cdot[(2+3(2+404:a)-612:6]=420\bigg|_{-2} \Rightarrow\\ \\ \Rightarrow2\cdot[(2+3(2+404:a)-102]=418\bigg|_{:2} \Rightarrow 2+3(2+404:a)-102=209\bigg|_{+102}\Rightarrow\\ \\ \\\Rightarrow 2+3(2+404:a)=311|_{-2} \Rightarrow 3(2+404:a)=309|_{:3} \Rightarrow2+404:a=103|_{-2}\Rightarrow \\ \\ \Rightarrow 404:a=101\bigg|_{:101} \Rightarrow 4:a=1 \Rightarrow a=4$