What is the value of x 0.4x + 3.9 = 5.78

x = 4.7

Step-by-step explanation:

0.4x + 3.9 = 5.78

subtract 3.9 from each side

0.4x + 3.9-3.9 = 5.78-3.9

.4x = 1.88

divide by .4 on each side

.4x/.4 = 1.88/.4

x = 4.7

0.4x + 3.9 = 5.78       Subtract 3.9 on both sides

0.4x + 3.9 - 3.9 = 5.78 - 3.9

0.4x = 1.88      Divide 0.4 on both sides

x = 4.7

[proof]

0.4x + 3.9 = 5.78        Plug in 4.7 for "x"

0.4(4.7) + 3.9 = 5.78    

1.88 + 3.9 = 5.78

5.78 = 5.78

step-by-step explanation:

given that there are two triangles j'k'l' and jkl>

the former is got by dilating the second one.

when drawn on a grid, (graph paper) coordinates of vertices of first triangle is

(6,12)j, (9,6)k and (12,9)l

side jk has length = distance between j and k

=

side j'k'=distance between j' and k'

=

ie j'k'l' has sides 1/3 of that of corresponding sides of jkl.

hence scale factor of 1/3 is used to get j'k'l'from jkl