Multiply out
remember thatn (-) times (+)=(-) so
+3 times -4=-12
-12x=0
the only number that will work is 0 since 0 times anything=0
x=0
Answer:
- C) (x − 3)2 = 25
- C) Factor out 4 from 4x2 + 40x.
Step-by-step explanation:
1. Adding the square of half the x-coefficient to both sides of the equation will "complete the square." That square is 9, so the result on the right is 16+9 = 25. Only selection C matches.
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2. To complete the square, you want to be able to put the quadratic into the form a(x -h)^2 = -k. For the purpose, it is most convenient to first factor "a" from the given quadratic. Then you can determine "-h" to be half the x-coefficient inside the parentheses.
Here, that looks like ...
4(x² +10x) = 80 . . . . . . . . . . step 1: factor out 4
4(x² +10x +25) = 180 . . . . . add 25 inside parentheses and the same number (4·25) on the right side of the equation
4(x +5)² = 180 . . . . . . . . . . . written as a square
-5 - 12 = -17
Starts at -5 degrees, then it drops another 12, so you subtract 12 from -5.
-10+2b+8
-2+8b+8
Calculated sum
-2+8b
Answer is -2+8b
