How do you solve #10=-2/3(4x+5)#?

1 Answer
Feb 20, 2016

#x=-5#

Working out shown in a lot of detail!

Explanation:

Given:#" " 10=color(brown)(color(blue)(-2/3)(4x+5))#

Multiply out the brackets giving:

#" "10= color(brown)({color(blue)((-2/3))xx4x }" "+" "{color(blue)((-2/3))xx5})#

The 'squiggly' brackets (braces) are only there to group parts to make understanding easier. They serve no other purpose

#10=-8/3 x- 10/3#

Add #color(blue)(10/3)# to both sides

#color(brown)(10color(blue)(+10/3)=-8/3 x -10/3color(blue)(+10/3))#

#40/3=-8/3 x+0#

#40/3=-8/3 x#

Multiply both sides by#color(blue)( 3)#

#40/(cancel(3)) xx cancel(color(blue)(3)) = -8/(cancel(3)) x xxcancel(color(blue)(3))#

Divide both sides by 8, divide by 8 is the same as #xx1/8#

#40/8= -8/8 x#

So #" "-x=5" "# Notice the #x# is negative

Multiply both sides by (-1) giving

#x=-5#