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pls this is a simultaneous equation- one linear one quadratic a-2b =2 -------- (1). a²+b²+2a -3b =19 --------(2). pls I need it urgently thanks​

1 Answer

5 votes

Answer:

Hence a = 3.66 and -3.628

b = 0.834 and -2.634

Explanation:

Given the equations

a-2b =2 -------- (1)

a²+b²+2a -3b =19 --------(2).

From 1;

a = 2 + 2b

Substitute into 2

(2+2b)²+b²+2a -3b =19

Expand

4 + 8b + 4b²+b²+2(2+2b)-3b = 19

4b²+b²+8b+4b+4+4-3b = 19

5b²+9b+8 = 19

5b²+9b-11 = 0

b = -9±√81+4(55)/2(5)

b= -9±√301/10

b = -9+17.34/10 and -9-17.34/10

b = 8.34/10 and -26.34/10

b = 0.834 and -2.634

Since a = 2+2b

a = 2+2(0.834)

a= 2 +1.668

a = 3.668

Also

a = 2+2(-2.634)

a = 2 - 5.628

a = -3.628

Hence a = 3.66 and -3.628

b = 0.834 and -2.634

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