Answer:
-7
Step-by-step explanation:
7.
step-by-step explanation:
the coefficient multiplies the variable.
it is -7.
Answer:
x^2 +4x+4 = 4
Step-by-step explanation:
To complete the square take the coefficient of the x term
4
Divide by 2
4/2 =2
Square it
2^2 =4
Add it to both sides of the equation
x^2 +4x+4 = 4

just a plain vanilla substitution
Answer:
11in
Step-by-step explanation:
a^2+b^2=c^2 when c is the hypotenuse
10^2+sqrt21^2=c^2
100+21=c^2
121=c^2
11=c