y x 2 + y x 4 + y x 6 + y x 8 + ... + y x 100 = 5100

⇒ y x (2 + 4 + 6 + 8 + ... + 100) = 5100

⇒ y x \(\dfrac{\left(100+2\right)\times\left[\left(100-2\right):2+1\right]}{2}\)= 5100

⇒ y x \(\dfrac{102\times50}{2}\)= 5100

⇒ y x 2550 = 5100

⇒ y = 5100 : 2550

⇒ y = 2

=>y×(2+4+6+8+...+100)=5100=>y×(100+2)×50:2=5100=>y×2500=5100=>y=25005100​=2

(-3) + 4 + 36 + (-17)

= [(-3) + (-17)] + (4 + 36)

= -20 + 40

= 20

(-3) + 4 + 36 + (-17)

= [(-3) + (-17)] + (4 + 36)

= -20 + 40

= 20

Gọi số phải tìm là ab. Theo bài ra ta có
ab = 5 × (a + b)
10 × a + b = 5 × a + 5 × b
10 × a – 5 × a = 5 × b – b
(10 – 5) × a = (5 – 1) × b
5 × a = 4 × b
Từ đây suy ra b chia hết cho 5. Vậy b bằng 0 hoặc 5.
+ Nếu b = 0 thì a = 0 (loại)
+ Nếu b = 5 thì 5 × a = 20, vậy a = 4.
Số phải tìm là 45.

                                                 ~~HT~~

Gọi số cần tìm là ab

Ta có:

ab = 5(a + b)

10a + b = 5a + 5b

10a - 5a = 5b - b

5a = 4b 

5a ⋮ 5 ⇒ 4b ⋮ 5 ⇒ b ⋮ 5 ⇒ b = 0 hoặc b = 5

Nếu b = 0  thì a = 0 (loại)

Nếu b = 5 thì 5a = 20 ⇒ a = 20 : 5 = 4

Vậy số cần tìm là 45

\(35.25+25.41+64.65\)

\(=25.\left(35+41\right)+64.65\)

\(=25.76+64.65\)

= \(1900+4160\)

\(=6060\)

35.25 + 25.41 + 64.65

= 875 + 1025 + 4160

= 1800 + 4160

= 5960

Okay nha bn

\(12.35+35.182-35.94\)

\(=35.\left(12+182-94\right)\)

\(=35.100\)

\(=3500\)

\(12.35+35.182-35.94\\ =35.\left(12+182-94\right)\\ =35.100=3500\)

\(\dfrac{\left(3^{10}.11+3^{11}.5\right)}{3^9}.5^0=\dfrac{3^9.\left(3.11+3^2.5\right)}{3^9}.1\\ =33+9.5=33+45=78\)

\(12.35+35.182+35.94=35.\left(12+182+94\right)\\ =35.288=10080\)

\(12.35+35.182+35.94\)

\(=35.\left(12+182+94\right)\)

\(=35.288\)

\(=10080\)

\(\left(a\right):78+58x50-58x25=78+58x\left(50-25\right)\\ =78+58x25=78+1450=1528\\ \left(b\right):326x78+327x22=326x78+326x22+1x22=326x\left(78+22\right)+22\\ =326x100+22=32600=32622\\ \left(c\right):27x39+27x63-2x27=27x\left(39+63-2\right)=27x100=2700\\ \left(d\right):48x19+48x115+134x52=48x\left(19+115\right)+134x52=48x134+134x52\\ =134x\left(48+52\right)=134x100=13400\)

a, \(78+58\times50-58\times25\)

\(=78+58\times\left(50-25\right)\)

\(=78+58\times25\)

\(=78+1450=1528\)

b, \(326\times78+327\times22\)

=\(326\times78+\left(326+1\right)\times22\)

\(=326\times78+326\times22+22\)

= \(326\times\left(78+22\right)+22\)

\(=326\times100+22\)

\(=32600+22\)

\(=32622\)

c, \(27\times39+27\times63-2\times27\)

\(=27\times\left(39+63-2\right)\)

\(=27\times100\)

\(=2700\)

d, \(48\times19+48\times115+134\times52\)

= \(48\times\left(19+115\right)+134\times52\)

\(=48\times134+134\times52\)

\(=134\times\left(48+52\right)\)

\(=134\times100\)

\(=13400\)

\(\dfrac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}\)

\(=\dfrac{2^{10}.3^9.\left(3-2\right)}{2^9.3^{10}}\)

\(=\dfrac{2^{10}.3^9.2}{2^9.3^{10}}\)

\(=\dfrac{2^{11}.3^9}{2^9.3^{10}}\)

\(=\dfrac{2^2}{3}\)

\(=\dfrac{4}{3}\)

ai xog trc thì mik tick nhé! Mik cần gấp