we are given

we can solve for x
We can isolate x
step-1: Multiply both sides by b/a


step-2:Add 12 both sides


step-3: combine right side

step-4:Divide both sides by 2
..............Answer
-2 -10 -3
-7 0 -8
-6 -5 -4
That's the square, it was a fun puzzle :)
(4 hundred + 0 tens + 5 ones) + (1 ten) = 4 hundred + 1 ten + 5 ones
... = 415
The 15% tip would be 50*0.15=$7.5
2. (D)
3. (B) Hope it helps