Toán Lớp 7: ai làm đc mình vote 5 sao tìm x,y a)(x-3)mũ 2=9 b)(x+6) mũ 2=25 c)(y-7)mũ 2-4=32 d)15-(y+2)=14

Question

Toán Lớp 7:  ai làm đc mình vote 5 sao tìm x,y a)(x-3)mũ 2=9 b)(x+6) mũ 2=25 c)(y-7)mũ 2-4=32 d)15-(y+2)=14

tuyetanhthu · Answer

đáp án

tonhu12 · Answer

Giải đáp:       Lời giải và giải thích chi tiết:   a) (x-3)^2=9   &hArr; (x-3)^2=(3)^2   &hArr;  ( left[  begin{array}{l}x-3=3  x-3=-3 end{array}  right. )   &hArr;  ( left[  begin{array}{l}x=6  x=0 end{array}  right. )   Vậy x  in {0;6}   b) (x+6)^2=25   &hArr; (x+6)^2=5^2   &hArr;  ( left[  begin{array}{l}x+6=5  x+6=-5 end{array}  right. )   &hArr;  ( left[  begin{array}{l}x=-1  x=-11 end{array}  right. )   Vậy x  in {-1;-11}   c) (y-7)^2-4=32   &hArr; (y-7)^2=36   &hArr; (y-7)^2=(6)^2   &hArr;  ( left[  begin{array}{l}y-7=6  y-7=-6 end{array}  right. )   &hArr;  ( left[  begin{array}{l}y=13  y=1 end{array}  right. )   Vậy y  in {1;13}   d) 15-(y+2)=14   &hArr; 15-14=y+2   &hArr; 1=y+2   &hArr; y=-2+1   &hArr; y=-1   Vậy y  in {-1}