How to solve 5 * (104-x-x-40) = 4x-30

How to solve 5 * (104-x-x-40) = 4x-30

5(64-2x)=4x-30
320-10x=4x-30
14x=350
x=125/7

How to solve the equation x + 4x = 40

x^2+4x=40
x^2+4x+4=44
(x+2)^2=44
x+2=±√44=±2√11
x=-2±2√11

Let [x] denote the largest integer not greater than x, then the number of real number solutions of equation 4x2-40 [x] + 51 = 0 is______ ．

If [x] denotes the largest integer not greater than x, that is, X-1 ＜ [x] ≤ x, and [x] = 110x2 + 5140, that is, X − 1 ＜ 110x2 + 5140 ≤ x, the solution is: X ∈ [32, 72) ∪ (132172), so [x] = 1, 2, 3, 6, 7, 8, substituting, all do not hold, then the number of solutions is 0, so the answer is: 0

Equation 4Y = 1-2 / 3Y

That is Y & # 178; + 8y / 3 = 2 / 3
y²+8y/3+16/9=2/3+16/9
(y+4/3)²=22/9
y+4/3=±√22/3
y=(-4-√22)/3,y=(-4+√22)/3

Can 4x & # 178; + 7x-8 = 0 be multiplied by a cross?

Cross multiplication is usually obtained only when the equation has integer roots or rational roots
The root of this equation is irrational, so we can only use formula method

How to solve 4Y + 9y = 123y-7x + 5Z = 19 / 43y-2z = 1 with univariate cubic equation?
Urgent, urgent, want detailed point, had better say why such solution

4Y+9Y=12 Y=12/13 3Y-2Z=1 Z=23/26 7X+5Z=19/4 X=34/728
It's called cubic equation of three variables. Cubic equation of one variable is not so simple

X ten (2x-100) = 4400

3x＝4400＋100
3x＝4500
x＝1500

A: 3Y / - 2 = 3Y / 2 B: - Y / - 6x = 6x / Y C: - 4Y / 3x = 4Y / 3x D: - 3Y / 8x = - 3Y / 8x

The following format from go to right is correct:
A: 3Y / - 2 = 3Y / 2 error, one minus sign missing
B: - Y / - 6x = 6x / y error, wrong numerator and denominator position
C: - 4Y / 3x = 4Y / 3x error, one minus sign missing
D: - 3Y / 8x = - 3Y / 8x pairs

(x / 5 + 60) + (x / 4-60) + 220 = x 4x + 5x + 4400 = 20x, how is it deduced
（x/5+60）+（x/4-60）+220=x
4x+5x+4400=20x
Excuse me, how to deduce it. I forgot all my old knowledge

x/5+60）+（x/4-60）+220=x
Multiply both sides by 20 and you'll get
4x+1200+5x-1200+4400=20x
4x+5x+4400=20x
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The solution equation is y △ 3.2-7 = 3 3Y + 5.4 = 12
y÷3.2-7=3
3y+5.4=12

y=32
y=11/5