Toán Lớp 6: A) 5¹⁶:5¹⁴+2.2³-2021⁰ B) X+35=42 C) 2x+5=25 D) 3.(5-X)=-30

Question

Toán Lớp 6:  A) 5¹⁶:5¹⁴+2.2³-2021⁰ B) X+35=42 C) 2x+5=25 D) 3.(5-X)=-30

thucquyenlan · Answer

a) 5^18:5^14+2.2^3-2021^0   =5^4+2.8-1   =625+16-1   =640   b) x+35=42   x=42-35   x=7   c) 2x+5=25   2x=25-5   2x=20   x=20:2   x=10   d) 3.(5-x)=-30   5-x=-30:3   5-x=-10   x=5-(-10)   x=15   Xin hay nhất

ngocle44 · Answer

$a)$ $5&sup1;⁶:5&sup1;⁴+2 cdot 2&sup3;-2021⁰$   $=(5&sup1;⁶:5&sup1;⁴)+(2 cdot 2&sup3;)-2021⁰$   $=25+16-1$   $=40$      $b)$ $x+35=42$   $&rArr;x+35-35=42-35$   $&rArr;x=7$   Vậy $x=7$   $c)$ $2x+5=25$   $&rArr;2x+5-5=25-5$   $&rArr;2x=20$   $&rArr; dfrac{2x}{2}= dfrac{20}{2}$   $&rArr;x=10$   Vậy $x=10$   $d)$ $3 left(5-x right)=-30$   $&rArr; dfrac{3 left(5-x right)}{3}= dfrac{-30}{3}$   $&rArr;5-x=-10$   $&rArr;5-x-5=-10-5$   $&rArr;-x=-15$   $&rArr; dfrac{-x}{-1}= dfrac{-15}{-1}$   $&rArr;x=15$   Vậy $x=15$