Ask the math problem, use the equation, please answer it in detail when the equation is listed! The fruit store shipped 100 kg of apples and oranges. It is known that four times the weight of apples is 120 kg more than three times the weight of oranges?

Ask the math problem, use the equation, please answer it in detail when the equation is listed! The fruit store shipped 100 kg of apples and oranges. It is known that four times the weight of apples is 120 kg more than three times the weight of oranges?

Let the weight of the apple be x and the weight of the orange be y
X + y = 100 (100 kg apple and orange)
4x-3y = 120 (four times the weight of an apple is 120 kg more than three times the weight of an orange)
The solution of the equations is x = 60, y = 40

Ask the equation
4X squared - y squared = 0 x squared - XY + 4 = 0

Y = 2x or y = - 2x is obtained from the square of 4x - y square = 0
Substituting into another equation
If x squared = 4, then x = 2 or - 2
3x squared = - 4 no solution
So x = 2 or - 2
Y = 4 or - 4

To solve this equation, (35-2x) (20-x) = 525

（35-2x）（20-x）=525
It unfolds well
700-75x+2x^2=525
2x^2-75x+175=0
(2x-5)(x-35)=0
x=5/2,x=35

How to solve the equation 20-2x = - X-1? There should be a detailed process. OK, I'll give you extra points! Please help me! O (∩)_ ∩)O

-2x+x=-1-20
-x=-19x=19