Question

solve the following system of equation using the method of substitution 2x + 3y=4and 5x + 8y = 9

Answer 1

2x+3y=4.....(i)
5x+8y=9.....(ii)
From equation (i),we have
2x+3y=4
2x=4-3y
x=4-3y/2.........(iii)

Put the value of 't' in equation (ii),we have
5x+8y=9
5(4-3y/2)+8y=9
20-15y/2+8y=9
20-15y+16y=9
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2
20-15y+16y=9×2
20+y=18
y=18-20
y=-2
Put the value of 'y=-2' in equation (i),we have
2x+3y=4
2x+3×-2=4
2x+(-6)=4
2x-6=4
2x=4+6
2x=10
x=10/2
x=5

Hence the value of x=5 and y=-2