Question

Solve (-r+5) (-r-8) using the formula x²+x(a-b) -ab

Answer 1

Step-by-step explanation:

(-r+5)(-r-8)

here

-r=x

5=a

-8=b

substute a,b and x values in x²+x(a-b)-ab

-r²+(-r)(5-(-8))-5×-8=0

-r²-r(5+8)+40=0

-r²-r(13)=-40

-r²-13r=40

-r²-r=40/13

-r²/r¹=40/13