solve for a and b: 47a+31b=63 31a+47b=15​

Question

solve for a and b: 47a+31b=63
31a+47b=15​

in progress 0
Genesis 1 week 2021-09-13T15:29:48+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-09-13T15:30:52+00:00

    Answer:

    (2, – 1)

    Step-by-step explanation:

    47a + 31b = 63

    31a + 47b = 15

    Cramer’s rule:

    Δ = \left[\begin{array}{cc}47&31\\31&47\end{array}\right] = 47² – 31²  = (47 – 31)(47 + 31) = 16 × 78 = 1248

    Δa = \left[\begin{array}{cc}63&31\\15&47\end{array}\right] = 63×47 – 31×15 = 2496

    Δb = \left[\begin{array}{cc}47&63\\31&15\end{array}\right] = 47×15 – 63×31 = – 1248

    a = Δa / Δ = 2496 ÷ 1248 = 2

    b = Δb / Δ = – 1248 ÷ 1248 = – 1

    (2 , – 1)

    0
    2021-09-13T15:30:55+00:00

    Step-by-step explanation:

    45a+31b=63 …….. (1)

    31a+47b=15 ……… (2)

    By multiplying (1) by 47 and (2) by 31

    Then, subtracting i from ii

    And solve it

Leave an answer

Browse
Browse

18:9+8+9*3-7:3-1*13 = ? ( )