Question

solve 4x-y=7;3x+4y=9 with substitution method in simultaneous equation

Answer 1

$\Large{\underline{\underline{\mathfrak{\bf{\red{Solution}}}}}}$

$\Large{\underline{\mathfrak{\bf{\orange{Given}}}}}$

• Equation, 4x - y = 7 --------(1)
• 3x + 4y = 9 ----------(2)

$\Large{\underline{\mathfrak{\bf{\orange{Find}}}}}$

• Value of x & y ,by substitution Method

$\Large{\underline{\underline{\mathfrak{\bf{\red{Explanation}}}}}}$

By, Equation (1)

➠ y = 4x - 7 -----------------(3)

Keep Value of y in equ(2)

➠ 3x + 4 * (4x - 7) = 9

➠ 3x + 16x - 28 = 9

➠ 19x = 9 + 28

➠ 19x = 37

➠ x = 37/19

Now, Keep Value of x in equ(3)

➠ y = 4 * 37/19 - 7

➠ y = (148 - 133)/19

➠ y = 15/19

$\Large{\underline{\underline{\mathfrak{\bf{\red{Hence}}}}}}$

• Value of x = 37/19
• Value of y = 15/19

__________________

$\large{\underline{\mathfrak{\bf{\orange{Answer\:Verification}}}}}$

Keep Value of x & y in equ(1)

➠ 4* 37/19 -15/19 = 7

➠ (148 - 15)/19 = 7

➠ 133/19 = 7

➠ 7 = 7

L.H.S. = R.H.S.

That's proved

__________________

Answer 2

Equation, 4x - y = 7 --------(1)

3x + 4y = 9 ----------(2)

Find

Value of x & y ,by substitution Method

Explanation

By, Equation (1)

➠ y = 4x - 7 -----------------(3)

Keep Value of y in equ(2)

➠ 3x + 4 * (4x - 7) = 9

➠ 3x + 16x - 28 = 9

➠ 19x = 9 + 28

➠ 19x = 37

➠ x = 37/19

Now, Keep Value of x in equ(3)

➠ y = 4 * 37/19 - 7

➠ y = (148 - 133)/19

➠ y = 15/19

Hence

Value of x = 37/19

Value of y = 15/19