7 0.75 100 _____ +_______=2 - _____ 0.8x 0.6x x^2

Question

7 0.75 100

_____ +_______=2 - _____

0.8x 0.6x x^2

Answer 1

4,2х + 0,6х =2(0.48х^2)-48

4,8х - 0,96х^2 + 48 =0

-0,96x^2 +4,8x +48 =0

D =4,8^2 -4(-0,96)(48)

D= 23,04 +184,32=корень из207,36

D = 14,4

X1 =( -4,8 + 14,4)/(2 x -0,96);  X1= 9,6/-1,92    X1 = - 5

X2 = (-4,8 - 14,4)/ -1,92;   X2 =-19,2 : -1,92;        X2 = 10       

Answer 2

0,8=8/10=4/5  ,  0,6=6/10=3/5  ,  0,75=75/100=3/4

7*5    3*5           100

-----+--------- + --------- - 2 =0

4*x    4*3*x          x² 

35x+5x+100-2x²

---------------------- =0

             4x² 

2x²-40x-100=0

x²-20x-50=0

x₁=10-5√6

x₂=10+5√6