Question

(4.a+4.b--2.x).(2.a+2.b+x) stiind ca x=5 si a+b=13

Answer 1

( 4 × a + 4 × b - 2 × x ) × ( 2 × a + 2 × b + x ) = 1 302

=[ 4 × ( a + b ) - 2 × 5 ] × [ 2 × ( a + b ) + 5 ] =

= ( 4 × 13 - 10 ) × ( 2 × 13 + 5 ) =

= ( 52 - 10 ) × ( 26 + 5 ) =

= 42 × 31 =

= 1 302

Answer 2

=(4(a+b)-2x5)x(2(a+b)+5)

=(4x13-10)x(2x13+5)

=(52-10)x(26+5)

=42x31

=1302