1/5 (a+10) = -3

Prob too late but I came up with -66? Use the distributive law for 1/5. Multiply the recipocal and you're left with a= -66

my skool maths isn't what it used to be...

but 1/5 = 0.2 so,

0.2*a + 0.2*10 = -3 (multiply the brackets)

0.2a + 2 = -3
0.2a = -5 (subtract 2 from both sides)

a = -25 (multiply both sides by 5)

It has been a few years though.:)