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Q3). 0.4x + 0.3y = 1.7
0.7x - 0.2y = 0.8
Solve it by using substitution method.​


Q3 04x 03y 17 07x 02y 08Solve It By Using Substitution Method class=

Sagot :

[tex]▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ { \huge \mathfrak{Answer}}▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ ▪ [/tex]

The values of :

  • [tex]x = 2[/tex]

  • [tex]y = 3[/tex]

The given equations are :

  • [tex]0.4x + 0.3y = 1.7[/tex]

  • [tex]0.7x - 0.2y = 0.8[/tex]

now, let's multiply both the equations with 10 on both sides.

so, now our equations will be :

  • [tex]4x + 3y = 17[/tex]

  • [tex]7x - 2y = 8[/tex]

from Equation second :

  • [tex]7x - 2y = 8[/tex]

  • [tex]2y = 7x - 8[/tex]

  • [tex]y = \dfrac{7x - 8}{2} [/tex]

now, let's substitute the value of y from here into Equation first.

  • [tex]4x + 3y = 17[/tex]

  • [tex]4x +3 \bigg ( \dfrac{7x - 8}{2} \bigg) = 17[/tex]

  • [tex]4x + \dfrac{21x - 24}{2} = 17[/tex]

  • [tex] \dfrac{8x + 21x - 24}{2} = 17[/tex]

  • [tex] \dfrac{ 29x - 24 }{2} = 17[/tex]

  • [tex]29x - 24 = 34[/tex]

  • [tex]29x = 34 + 24[/tex]

  • [tex]29x = 58[/tex]

  • [tex]x = \dfrac{58}{29} [/tex]

  • [tex]x = 2[/tex]

here, we got the value of x = 2, let's plug it in equation second to find value of y :

  • [tex]7x - 2y = 8[/tex]

  • [tex]7(2) - 2y = 8[/tex]

  • [tex]14 - 2y = 8[/tex]

  • [tex]2y = 14 - 8[/tex]

  • [tex]2y = 6[/tex]

  • [tex]y = \dfrac{6}{2} [/tex]

  • [tex]y = 3[/tex]

And value of y = 3