Solve the quadratic equation
y=11-2x-2x^2
c)(i) x = -2.9 or 1.9
(ii) y+(3−2x−2x2)=11−2x−2x2
y=11−2x−2x2−3+2x+2x2
y=8
∴x=-1.8 or 0.8
(iii) y=11−2x−2x2
dydx=−2−4x
Gradient at x = 1 : −2−4(1)=−2−4=−6
Please my problem is(ii)
How did they get x=-1.8 and x=0.8?
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Asked by Alex Baba on 19th November, 2019
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8 months ago
But what they did is quite clear
(ii) you'll be getting is y=8. With that value ignore everything in the bracket on the Left hand side.
What you'll have is
y=11-2x-2x².
With that you can substitute y=8 and solve.