Step-by-step explanation:
this is the answer in the picture
Y=a(x-h)^2+k
vertex form is basically completing the square
what you do is
for
y=ax^2+bx+c
1. isolate x terms
y=(ax^2+bx)+c
undistribute a
y=a(x^2+(b/a)x)+c
complete the square by take 1/2 of b/a and squaring it then adding negative and postive inside
y=a(x^2+(b/a)x+(b^2)/(4a^2)-(b^2)/(4a^2))+c
complete square
too messy \
anyway
y=2x^2+24x+85
isolate
y=(2x^2+24x)+85
undistribute
y=2(x^2+12x)+85
1/2 of 12 is 6, 6^2=36
add neagtive and postivie isnde
y=2(x^2+12x+36-36)+85
complete perfect square
y=2((x+6)^2-36)+85
distribute
y=2(x+6)^2-72+85
y=2(x+6)^2+13
vertex form is
y=2(x+6)^2+13
S=4π<span>r<span>2 - this is the equation for the surface area of a sphere. We know that the radius (r) is 3.5 so here's how to solve this:
S = 4</span></span><span>π r2
S = 4</span><span>π (3.5)2
S = 4</span><span>π 12.25
S = 49</span><span>π
The surface area of a sphere with radius of 3.5 is 49</span><span>π.</span>
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