Question

Solve the simultaneous equation 2p - 3q = 4, 3p + 2q = 9. b. if 223= 87 find x​

Answer 1

Answer:

Step-by-step explanation:

Given the simultaneous equation 2p - 3q = 4 and 3p + 2q = 9, to get the value of p and q we will use elimination method.

2p - 3q = 4 ...................... 1 * 3

3p + 2q = 9 ..................... 2 * 2

Multiplying equation 1 by 3 and 3 by 2:

6p - 9q = 12

6p + 4q = 18

Subtracting both equation

-9q-4q = 12-18

-13q = -6

q = -6/-13

q = 6/13

Substituting q = 6/13 into equation 2

2p - 3(6/13) = 4

2p - 18/13 = 4

2p = 4+18/13

2p = (52+18)/13

2p = 70/13

p = 70/26

p = 35/13

Hence p = 35/13 and q = 6/13

b) If if 223ₓ = 87 find x

Using the number base system and converting 223ₓ  to base 2 will give us;

223ₓ = 2*x² + 2*x¹ + 3*x⁰

223ₓ  = 2x²+2x+3

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Substituting back into the equation, 2x²+2x+3 = 87

2x²+2x+3-87 = 0

2x²+2x-84 = 0

x²+x-42 = 0

On factorizing:

(x²+6x)-(7x-42) = 0

x(x+6)-7(x+6) = 0

(x+6)(x-7) = 0

x+6 = 0 and x-7 = 0

x = -6 and 7

Hence the value of x is 7 (neglecting the negative value)