Question

Show the lines in the system

0.1x - 0.8 y = 8

0.7x + 0.4y = -4

would intersect in a single point by writing the equations in a slope-intercept form.

Please express all fractions as reduced proper or improper fractions

y = ____________________________x -

y= ____________________________x -

Answer 1

0.1x-0.8y=8→⅛x-y=10 after dividing through by 0.8, y=x/8-10.

0.7x+0.4y=-4→7x/4+y=-10 after dividing through by 0.4, y=-7x/4-10.

So y=x/8-10=-7x/4-10, therefore x/8=-x/4, that is, x(⅛+¼)=0⇒x=0.

So y=-10.

Therfore the lines intersect at (0,-10).