To solve this equation, we use the rule that #a(b+c) = ab+ac#
Using this rule, we now find that
#-5x^2(-8x^2-5x)=(-5x^2*-8x^2)+ (-5x^2*-5x)#
Lets do the first bracket, #(-5x^2*-8x^2)#. First we look at the signs in front. They are both negatives, and since a negative multiplied by a negative equals a positive, we know the answer to #(-5x^2*-8x^2)# will be positive. Next we look at the coefficients, 5 and 8. Since #5*8=40#, we know the answer will include #40#. Finally, we look at the variables, which are both #x^2#. According to the rule #x^n * x^m=x^n+m#, we find that #x^2*x^2=x^2+2=x^4#. The last thing to do is combine all our values together, so
#+ and 40 and x^4 = +40x^4#
We then do the same process with the second bracket, #(-5x^2*-5x)#. Negative and a negative equals a positive, #5*5=25#, and (since #x=x^1#),
#x^2*x^1=x^2+1=x^3#
Combined together,
#+ and 25 and x^3=+25x^3#
Now if we look at our equation we have
#(40x^4)+(25x^3)#
Once we remove the brackets, we get our answer, which is
#40x^4+25x^3#
I hope I helped!
