CHAPTER 7. SOLVINGQUADRATIC EQUATIONS 7.5
(a) Use this formula to solve the equation:
2 x^2 + x− 3 = 0
(b) Solve the equation again, using factorisation, to see if the formula works for this
equation.
(c) Trying to derive thisformula to prove that it always works, Bjorn got stuck along
the way. His attempt hisshown below:
ax^2 + bx + c = 0
a +
b
x
+
c
x^2
= 0 Divided by x^2 where x�= 0
c
x^2
+
b
x
+ a = 0 Rearranged
1
x^2
+
b
cx
+
a
c
= 0 Divided by c where c�= 0
1
x^2
+
b
cx
=−
a
c
Subtracted
a
c
from both sides
∴
1
x^2
+
b
cx
+... Got stuck
Complete his derivation.
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(1.) 019h (2.) 019i (3.) 019j (4.) 019k (5.) 019m (6.) 019n
(7.) 019p (8.) 019q (9.) 019r (10.) 019s
