Heather used mental math to find the exact sum of 432 and 24. which strategy could heather have used?

To find the sum of 432 and 24 mentally.

Heather can add 3+2 in the tens place also known as 30 and 20 that is equivalent to 5 (tens)

Than,add 2+4 in the ones place that is equal to 6.

The 4 in the hundred doesn't change so just put the puzzle together.

You get 456 as the sum.

First subtract 10 from both side
y^2+6y-16=0
(y+8)(y-2)=0
-8 and 2