Answer:
? = 16
Step-by-step explanation:
x2 - 8x + ? = 42 + ?
1. Take the coefficient of the middle term 8x, which is 8 and divide it by 2. [tex]\frac{8}{2} = -4[/tex]. Then square it [tex]-4^{2} = 16[/tex]
2. Take 16 and add it to both sides: [tex]x^2 - 8x + 16 = 42 + 16[/tex]
2. Take half of the coefficient 8 that you divided by 2, which is 4 and insert 4 into the equation [tex](x -4)^2 = 58[/tex]
3. ? = 16
