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Answer:
Tamara incorrectly factored the whole expression.
Step-by-step explanation:
Note that
•21x=3·7·x;
•56xy=2·2·2·7·x·y.
Mark in bold all common factors, then GCF(21x,56xy)=7·x=7x.
Thus,
21x+56xy=7x(3+8y).
Hence, Tamara correctly found the GCF of numbers 21 and 56, but incorrectly factored the whole expression.
Vertex form:
y-k=a(x-h)^2
h=-2,k=-20,y=-12 when x=0
thus;
-12+20=a(0+2)^2
8=4a
a=2
Equation:
y+20=2(x+2)^2
y+20=2(x^2+4x+4)
f(x)=2(x^2+4x+4)-20
f(x)=2x^2+8x+8-20
f(x)=2x^2+8x-20