Question

Solve the following system of linear equations using graphing method substitution method or illumination method

Answer 1

Solving using substitution method

2x +5 = y ---i

3x -7y =20 ---ii

Substitute equation i into ii

3x -7(2x +5) = 3x - 14x -35

= -11x -35 =20

-11x =20+35 =55

x= 55/ -11 = -5

x = -5

Put the value x = -5 into equation 1

2(-5) +5 =y

-10+5 = y

y = -5

Therefore x = -5 , y = -5