1) 3 (29-5x) = x (x-5)

2) 24-x (3x+4) = 2 (15-2x)

3) (x+3) (x-7) + (x+5) (x-1) = 80

1) 3 (-5x+29) = x (x-5)

-x (x-5) + 3 (-5x+29) = 0

-x2-10x+87=0

D = (-10) ^2 - 4 * (-1) * 87 = 448

x1=--4√7 - 5

x2=-5+4√7

2) 24 - x (3x+4) = 2 (15-2x)

24-x (3x+4) = 2 (15-2x)

24-3x2-4x = 30-4x

-3x2-6 = 0

3x2+6 = 0

3x2 = - 6

упражнение действительных корней не имеет.

3) 1 (x+3) (x-7) + (x+5) (x-1) = 80

x2-7x+3x-21+x2-x+5x-5 = 80

2x²-106 = 0

2x² = 106

x2 = 53

x1 = + √53

x2 = - √53