Bonsoir,
A= -6 + 6 × (-3) + 5*[-9 +(-2)]
= -6 - 18 + 5 × ( -11)
= -6 - 18 - 55
= - 79
(tu calcules en premier les priorités: multiplication et parenthèses)
B= (1/9-3/5) ÷ (8/5 + 7/9)
=(1×5 / 9×5 - 3×9/5×9) ÷ (8×9/5×9 + 7×5/9×5)
(tu mets au même dénominateur)
=( 5/45 - 27/45) ÷ (72/45 + 35/45)
= -22/45 ÷ 107/45
= -22/45 × 45/107
= -22/107
C= 7/4 - 3/4 × 8/9
= 7/4 - 24/36
=7×9/ 4×9 - 24/36
=63/36 - 24/36
= 39/36 ( soit 13/12)
D= 2×10-² + 5 × 10-³ / 5×10⁴
=2+5 × 10 ^(-2+ (-3) / 5×10⁴
= 2× 10^(-5) / 10⁴
= 2×10^(-5)- ^(4)
= 2×10^(-9)
E=4 - (2-5)² / 4+5
= 4 - ( -3)² / 9
= 4-9 / 9
= -5/9