book Maths Puzzle Numerical Ability

the answer to the following should be 4/3a, however, I cannot understand how - please help! Thank you!!

1/1.5 + 1/1.5=

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book Other Question

4y-3(y+8)=12 can you please show how an tell how to solve how do you factor the trinomial? 9xsquared - 18x + 9 = 0

it would be wonderful if i could get the steps instead of just the answer, i just need help understanding how to solve the problem and others like it.