#color(brown)("Note that when multiplying or dividing, if the signs are")##color(brown)("different, then the answer is negative. On the other hand,")##color(brown)("if the signs are the same then the answer is positive.")#
Consider just the brackets part: #color(white)("d")-(23.3-43.5)#
What follows is not a normal mathematical way of writing it. However it is true!
#color(brown)("I adopted this approach to make what is happening very clear.")#
#color(blue)((-1)xx)color(green)((+23.3color(white)("dddd")"put with"color(white)("ddd")-43.5))#
Multiply everything inside the brackets by the #color(blue)(-1)# that is outside.
#color(green)( [color(white)(2/2)color(blue)((-1))xx(+23)color(white)(2/2) ]"put with"[color(white)(2/2) color(blue)((-1))xx(-43.5) color(white)(2/2)] )#
#color(green)( color(white)("ddd")[color(white)(2/2)-23color(white)(2/2)]color(white)("dddd")" put with "color(white)("dd")[color(white)(2/2)+43.5color(white)(2/2)]#
#color(white)("dddddddddddddddd")color(green)(-23+43.5)#
Which is the same as:
#color(white)("dddddddddddddddddd")color(green)(43.5-23 =20.5)#
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Putting it back together
With practice of this question type this will be what your working out could look like.
#color(green)(color(red)(-(23.3-43.5))-3.4 color(white)("dddd")->color(white)("dddd") color(red)(20.5) -3.4 = 17.1)#
