Question

4× + 3y = 9; 2× + 5y = 15​

Answer 1

Answer:

Answer

3y−2x=9;2x+5y=15

y=39+2x  Put it in second equation.

2x+5×39+2x=15

6x+45+10x=45

16x=0

x=0

y=39+2x=39+2(0)=3

Answer 2

4x + 3y = 9

2x + 5y = 15

EQUATION 1:

4x + 3y = 9

4x = 9 - 3y

4x = 3(3-y)

x = $\frac{3(3-y)}{4}$

Substituting x for $\frac{3(3-y)}{4}$ in equation 2:

EQUATION 2:

2x + 5y = 15

2($\frac{3(3-y)}{4}$) + 5y = 15

(since it's multiplication 2 and 4 can get cancelled which will result in 2 as the denominator)

$\frac{3(3-y)}{2}$ + 5y = 15

lcm = 2

$\frac{3(3-y)+10y}{2}$ = 15

3(3-y) + 10y = 15 × 2

9 - 3y + 10y = 30

9 + 7y = 30

7y = 30-9

7y = 21

y = $\frac{21}{7}$

y = 3

Therefore

x = $\frac{9-3y}{4}$

x = $\frac{9-3(3)}{4}$

x = $\frac{9-9}{4}$ x = $\frac{0}{4}$ x = 0

VERIFICATION:

4(0) + 3(3) = 9

0 + 9 = 9

0 = 9-9

LHS = RHS

hence verified

2(0) + 5(3) = 15

0 + 15 = 15

0 = 15-15

LHS = RHS

hence verified.

Hope it helps

have a great day