Choice B is the correct answer. To eliminate y, multiply the second equation by 2.
Step 1: Multiply the second equation by 2:
10x−4y=22
Step 2: Add to the first equation:
(3x+4y)+(10x−4y)=27+2213x=49x=1349
Non-integer. - First: 3(5)+4(3)=15+12=27 ✓
- Second: 5(5)−2(3)=25−6=19 eq11
Step 1: Multiply second by 2:
10x−4y=38
Step 2: Add:
13x=65x=5
Step 3: Substitute:
3(5)+4y=2715+4y=27y=3
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💡 Strategic Tip: Multiplying by 2 turned the −2y into −4y to match the +4y in the first equation.
Choice A is incorrect because3(4)+4(415)=12+15=27 ✓, but 5(4)−2(415)=20−7.5=12.5 eq19.
Choice C is incorrect because3(3)+4(4.5)=9+18=27 ✓, but 5(3)−2(4.5)=15−9=6 eq19.
Choice D is incorrect because3(6)+4(2.25)=18+9=27 ✓, but multiplication in second fails.