(4^2).x-(3^2).x=49
Help me, please
1,4 x 15/49 - (4/5 + 2/3) : 2 1/5
tìm X:
(2,8x - 32) : 2/3 + -90
help me, please !!!!!~
a: \(=\dfrac{7}{5}\cdot\dfrac{15}{49}-\dfrac{12+10}{15}:\dfrac{11}{5}\)
\(=\dfrac{3}{7}-\dfrac{22}{15}\cdot\dfrac{5}{11}=\dfrac{3}{7}-\dfrac{2}{3}=\dfrac{9-14}{21}=\dfrac{-5}{21}\)
b: =>2,8x-32=-60
=>2,8x=-28
hay x=-10
Tìm x
4× (x+3)= 2 ×(x+1)+20
Help me please nhanh, đúng thì tick nha
4× (x+3)= 2 ×(x+1)+20
4 x + 12 = 2x + 2 + 20
2x = 10
x = 5
4.(x+3)=2.x+2+20
12+4x =2x+22
4x =2x+10
2x =10
x =10:2
x =5
Nhớ phải giữ lời hứa đó!
Học tốt!
Tìm x: (x-2)/16=-4/(2-x)
Help me, please!!!
\(\frac{x-2}{16}=\frac{-4}{2-x}\)
\(\Leftrightarrow\frac{x-2}{16}+\frac{4}{2-x}=0\)
\(\Leftrightarrow\frac{\left(x-2\right)\left(2-x\right)+4.16}{16\left(2-x\right)}=0\)
\(\Leftrightarrow\left(x-2\right)\left(2-x\right)+64=0\)
\(\Leftrightarrow-\left(x-2\right)\left(x-2\right)=-64\)
\(\Leftrightarrow-\left(x-2\right)^2=-8^2\)
\(\Leftrightarrow\left(x-2\right)^2=8^2\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=8\\x-2=-8\end{cases}\Leftrightarrow\orbr{\begin{cases}x=10\\x=-6\end{cases}}}\)
P/s: Mik nghĩ bài này lớp 8 thì đúng hơn vì nó liên quan đến hằng đẳng thức
Nếu là lp 8 thì giải theo cách này nha:
\(\Rightarrow\left(x-2\right).\left(2-x\right)=16.\left(-4\right)\)
\(2x-x^2-4+2x=-64\)
\(-x^2+4x-4=-64\)
\(-\left(x+2\right)^2=-64\)
\(\Rightarrow\left(x+2\right)^2=8^2\)
\(\Rightarrow\orbr{\begin{cases}x+2=8\\x+2=-8\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=6\\x=-10\end{cases}}\)
Nâng cao lớp 7 cũng là chuyên đề Hằng đẳng thức mà bạn Moon!!
5/8 + 0,2 : | -x/4 + 2/5 | = 3/2
help me please T o T
Rút gọn:
a) -3x(x+2)^2 + (x+3)(x-1)(x+1) - (2x-3)^2
b) (x-3)(x+3)(x+2)- (x-1)(x2-3) - 5x(x+4)2-(x-5)2
please help me!!
Rút gọn:
a) -3x(x+2)^2 + (x+3)(x-1)(x+1) - (2x-3)^2
b) (x-3)(x+3)(x+2)- (x-1)(x2-3) - 5x(x+4)2-(x-5)2
please help me!!
a)\(-3x\left(x+2\right)^2+\left(x+3\right)\left(x-1\right)\left(x+1\right)-\left(2x-3\right)^2\)
\(=-3x.\left(x^2+2.x.2+2^2\right)+\left(x^2+x+3x-3\right).\left(x+1\right)-\left(2x\right)^2-2.2.x.\left(-3\right)+\left(-3\right)^2\)
\(=-3x.\left(x^2+4x+4\right)+\left(x^2+\left(x+3x\right)-3\right).\left(x+1\right)-4x+12x+9\)
\(=-3x.\left(x^2+4x+4\right)+\left(x^2+4x-3\right)\left(x+1\right)-4x+12x+9\)
\(=-3x^3-12x^2-12x+x^3+4x^2-3x+x^2+4x-3-4x+12x+9\)
\(=\left(-3x^3-x^3\right)+\left(-12x^2+4x^2+x^2\right)+\left(-12x-3x+4x-4x+12x\right)+\left(-3+9\right)\)
\(=-2x^3-7x^2-3x+6\)
b)\(\left(x-3\right)\left(x+3\right)\left(x+2\right)-\left(x-1\right)\left(x^2-3\right)-5x\left(x+4\right)^2-\left(x-5\right)^2\)
\(=\left(x.\left(x+3\right)-3\left(x+3\right)\right)\left(x+2\right)-\left(x.\left(x^2-3\right)-1\left(x^2-3\right)\right)-5x\left(x+4\right)^2-\left(x-5\right)^2\)
\(=\left(x.x+x.3-3.x+\left(-3\right).3\right)\left(x+2\right)-\left(x.x^2+x.\left(-3\right)-1.x^2+\left(-1\right).\left(-3\right)\right)-5x.x+\left(-5x\right).4-x^2-2x5+5^2\)
\(=\left(x^2+3x-3x-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^2+\left(3x-3x\right)-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^2-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=x^3+2x^2-9x-15-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^3-x^3\right)+\left(2x^2-x^2-5x^2-x^2\right)+\left(-9x-3x-20x-10x\right)+\left(-18+3+25\right)\)
\(=-5x^2-42x+10\)
1.
A= 2.8^4.27^2+4.9^9/2^7.6^7+2^7.40.9^4
B= (2/3)^3 . (-3/4)^2.(-1)^5/(22/5)^2.(-5/12)^3
2. Tìm số tự nhiên x, biết:
a, 4^x+4^x+3= 4160
b, 2^x-1+5.2^x-2=7/32
Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!Please!!!
1, Tính
a, 7/8 - 2/3
b, 7/8 - 2/3 × 3/4
2, Tìm X
a, 5/8 - x = 5/9
b, 3/4 : x = 2/5
( please help me!!
\(1-\)\(a,\frac{7}{8}-\frac{2}{3}=\frac{21}{24}-\frac{16}{24}=\frac{5}{24}\)
\(b,\frac{7}{8}-\frac{2}{3}\times\frac{3}{4}=\frac{7}{8}-\frac{1}{2}=\frac{7}{8}-\frac{4}{8}=\frac{3}{8}\)
\(2-\)\(a,\frac{5}{8}-x=\frac{5}{9}\)
\(x=\frac{5}{8}-\frac{5}{9}\)
\(x=\frac{5}{72}\)
\(b,\frac{3}{4}:x=\frac{2}{5}\)
\(x=\frac{3}{4}:\frac{2}{5}\)
\(x=\frac{15}{8}\)
1, Tính:
\(\frac{7}{8}\) - \(\frac{2}{3}\) = \(\frac{21}{24}\) - \(\frac{16}{24}\) = \(\frac{5}{24}\)
\(\frac{7}{8}\) - \(\frac{2}{3}\) x \(\frac{3}{4}\) = \(\frac{7}{8}\) - \(\frac{1}{2}\) = \(\frac{7}{8}\) - \(\frac{4}{8}\) = \(\frac{3}{8}\)
2, Tìm x
\(\frac{5}{8}\)- x = \(\frac{5}{9}\)
x = \(\frac{5}{8}\)- \(\frac{5}{9}\)
x = \(\frac{5}{72}\)
\(\frac{3}{4}\): x = \(\frac{2}{5}\)
x = \(\frac{3}{4}\) : \(\frac{2}{5}\)
x = \(\frac{15}{8}\)
tìm x ,biết : ( 8x - 4x^2 -1 ) ( x^2 +2x +1 )= 4(x^2 +x+1 ) ...Please !! Heo mì !!!(Help me !!! )
\(\left(8x-4x^2-1\right)\left(x^2+2x-1\right)=4\left(x^2+x+1\right)\)
\(11x^2+6x-4x^4-1=4x^2+4x+4\)
\(11x^2+6x-4x^4-4x^2-4x-4=0\)
\(7x^2+2x-4x^4-5=0\)
\(\left(x-1\right)\left(x-1\right)\left(-4x^2-8x-5\right)=0\)
bn lm nốt nha , ko có dấu hoặc nên mk làm đến đây thôi
Cảm ơn nha ! Nhưng sao mình ko ấn đúng cho bạn được !? hic