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<h3>I'm solving it using substitution method:-</h3>
<h3>7x+2y=3 {given}</h3>
<h3>=>7x=3-2y</h3>
<h3>=>x=(3-2y)/7-------(1)</h3>
<h3>x-3y=30 {given}</h3>
<h3>=>x=30+3y</h3>
<h3>=>(3-2y)/7=30+3y {putting the value of x from eqn 1}</h3>
<h3>=>3-2y=210+21y</h3>
<h3>=>3-210=21y+2y</h3>
<h3>=>-207=23y</h3>
<h3>=>y= -207/23= -9</h3>
<h3>putting the value of y on eqn(1):-</h3>
<h3>x=(3-2y)/7</h3>
<h3>x=>(3-2(-9))/7=(3+18)/7=21/7=3</h3>
<h2>Hence, x=3, y= -9</h2>
✌️✌️❤️❤️
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Answer:
a)ab=10cm,r=10cmhgggkoifytewubbbcgkjjgyuuresgbvcguytrewsdyoohfutrfhje
A = (a+b)/2
2*A = 2*(a+b)/2 ... multiply both sides by 2
2A = a+b
2A-a = a+b-a ... subtract 'a' from both sides to isolate b
2A-a = b
b = 2A-a
Answer: b = 2A-a